Synthesis and Characterization of Nanostructured Conducting Polymers and Their 
Composites with Noble Metal Nanoparticles 
 
by 
 
Selcuk Poyraz 
 
 
 
 
A thesis submitted to the Graduate Faculty of  
Auburn University  
in partial fulfillment of the  
requirements for the Degree of  
Master of Science 
 
Auburn, Alabama 
December 13, 2010 
 
 
 
 
Keywords: conducting polymers, noble metal nanoparticles, composite nanostructures 
 
 
Copyright 2010 by Selcuk Poyraz 
 
 
Approved by 
 
Xinyu Zhang, Chair, Assistant Professor of Polymer and Fiber Engineering 
Peter Schwartz, Professor of Polymer and Fiber Engineering  
Sabit Adanur, Professor of Polymer and Fiber Engineering 
Maria Lujan Auad, Assistant Professor of Polymer and Fiber Engineering 
 
 
 
 
 
 
 
 
 
 
 
 
Abstract 
 
 
Conducting polymers and noble metals were combined in one nanostructure to produce 
materials with academic and industrial interest gathering properties. Novel, facile, one-step and 
seeding-template-assisted oxidative polymerization reactions of pyrrole were conducted to 
synthesize such nanocomposites made up of Polypyrrole (PPy) nanofibers decorated by the noble 
metal (Au, Pt) nanoparticles. Enhanced sensing properties and catalytic capability were meant to 
be provided in a 2-D nanocomposite matrix. As the reaction media, four different noble metal 
salts? aqueous electrolyte solutions were used. AuCl, PtCl
2
, PtCl
4 
and HAuCl
4
 salts were, 
individually, dissolved in water to prepare these solutions. They eliminated the use of oxidative 
agents like ammonium peroxydisulfate and also large amounts of in/soluble templates like 
zeolites, opals and surfactants by both acting as the dopant and the oxidant for pyrrole. 
Vanadium pentoxide (V
2
O
5
) sol-gel nanofibers were assisting, as the seeding-template, to ensure 
fibrillar morphology during the reactions. 
The goal of this study was to build a substantial background for the futuristic industrial 
applications, i.e., fuel-cell membranes of such nanocomposites by utilizing the knowledge 
obtained from the chemical analysis and the instrumental characterizations.  
To control, investigate, improve and characterize several properties of conducting 
polymer based nanocomposites and to determine the effects of the electrolyte concentration 
besides the other reaction parameters on the final product morphology and properties, the above 
mentioned project was undertaken in details throughout the Master?s degree.  
 
?
ii
 
 
 
 
 
Acknowledgments 
 
 
The author would like to express his thanks to his advisor and mentor, Dr. Xinyu Zhang, 
for his time, guidance, and judicious advice. The author also expresses his gratitude to all his 
committee members for their suggestions.  
The author is owed special thanks to his research group partner, Zhen Liu, for his 
collaboration, guidance, and precious advice. Appreciation is also owed to another previous 
research group partner, Johannes B?r, for his valuable contributions during his summer 
internship. Thanks to the Department of Polymer and Fiber Engineering for welcoming 
environment. The author would like to thank the Turkish Ministry of Education for the aid in 
sponsoring him during his studies.  
The author finally would like to express his most sincere thanks to his parents, 
Kemalettin and Alime, and his big sister, Seval, for their sincere love. The author?s appreciation 
from the bottom of his heart also goes to his fianc?e, Tuba, for her ongoing encouragement and 
love. The author also expresses his gratitude to all his friends in Polymer and Fiber Engineering 
Department and in Auburn, for providing him ongoing support throughout these two years. He 
also would like to express his infinite appreciation to God for bestowing him skills and ability to 
think.   
 
 
 
 
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iii
 
 
 
 
 
Table of Contents 
 
 
Abstract.........................................................................................................................................ii 
Acknowledgments........................................................................................................................iii 
List of Tables ..............................................................................................................................vii 
List of Figures............................................................................................................................viii 
Chapter 1 Literature Review......................................................................................................... 1 
 1.1 Introduction................................................................................................................. 1 
 1.2 Types of Electronic Conducting Polymers (ECPs)..................................................... 8 
1.2.1 Polyacetylene ............................................................................................... 8 
 1.3 Intrinsically Conducting Polymers (ICPs)................................................................ 13 
1.3.1 Polyaniline (PANI) .................................................................................... 14 
1.3.2 Polythiophene (PTh) and Poly (3-hexylthiophene) (P3HTh) .................... 17 
1.3.3 Poly (3, 4-ethylenedioxythiophene) (PEDOT) .......................................... 19 
1.3.4 Polypyrrole (PPy)....................................................................................... 21   
 1.4 Theory of Conductivity and the Conduction Mechanism of Conducting  
 Polymers ............................................................................................................. 26 
 
Chapter 2 Synthesis of Conducting Polymer/Noble Metal Particle Nanocomposites................ 29 
 2.1 Introduction............................................................................................................... 29 
 2.2 Experimental Section................................................................................................ 33 
2.2.1 Materials .................................................................................................... 33 
2.2.2 Synthesis Methods ..................................................................................... 34 
 
?
iv
2.2.2.1 Synthesis of Polypyrrole (PPy) Granules and Fibers.................. 34 
2.2.2.2 Preparation of Standard Aqueous Noble Metal Salt Solutions... 35 
2.2.2.3 Synthesis of Polypyrrole (PPy) Nanofiber/Noble Metal 
Nanoparticle Composites............................................................ 36 
2.2.2.4 Purification of As-prepared Samples.......................................... 37 
2.2.3 Preparation of Electrolytes for the Cyclic Voltammetry (CV) Applications 
and Electrochemical Characterization .................................................... 38 
 
2.2.4 Preparation of Electrodes for the Cyclic Voltammetry (CV)  
Applications ............................................................................................ 39 
 
2.2.5 Microwave Initiated Carbonization of Nanocomposite Samples .............. 39 
2.2.6 Instruments and Characterization Methods ............................................... 42 
Chapter 3 Results and Discussions ............................................................................................. 45 
 3.1 Introduction............................................................................................................... 45 
 3.2 Different Characterization and Application Results and Discussions ...................... 46 
3.2.1 SEM Characterization Results ................................................................... 46 
3.2.2 TEM Characterization Results................................................................... 63 
3.2.3 TGA Characterization Results ................................................................... 67 
3.2.4 EDX Analysis Results................................................................................ 74 
3.2.5 FT-IR Characterization Results ................................................................. 77 
3.2.6 SEM Characterization Results of Microwave Treated Nanocomposites... 81 
3.2.7 TGA Characterization Results of Microwave Treated Nanocomposites... 86 
3.2.8 EDX Analysis Results of Microwave Treated Nanocomposites ............... 91 
3.2.9 FT-IR Characterization Results of Microwave Treated 
Nanocomposites...................................................................................... 93 
3.2.10 Four Probe Conductivity Measurement Results of Different Polymeric and 
Nanocomposite Structures ...................................................................... 95 
 
?
v
 
3.2.11 Cyclic Voltammetry (CV) Application Results of Different Polymeric and 
Nanocomposite Structures ...................................................................... 98 
Chapter 4 Conclusions and the Future Work............................................................................ 103 
 4.1 Conclusions............................................................................................................. 103 
 4.2 Future Work............................................................................................................ 104 
References................................................................................................................................. 105 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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vi
 
?
vii
 
 
 
 
 
List of Tables 
 
 
Table 1 Number of journal articles published annually related to conducting polymers ............. 5 
Table 2 Scientific papers published on conducting polymers categorized into main topics ........ 5 
Table 3 Comparison of metals, plastics and conducting polymers in different ways................... 7 
Table 4 Different attributes of ICPs............................................................................................ 26 
Table 5 Amounts of the nanocomposite yields obtained from different noble metal  
solutions ......................................................................................................................... 38 
 
Table 6 Summary of the EDX analysis results of all different nanocomposite structures ......... 75 
Table 7 Summary of the EDX analysis results of the microwaved nanocomposite structures .. 92 
Table 7 Summary of the calculated values of samples used for conductivity measurements .... 97 
 
 
 
 
 
 
 
 
 
 
 
 
List of Figures 
 
 
Figure 1 Cis- and trans- polyacetylene ......................................................................................... 2 
Figure 2 Free-standing polyacetylene film ................................................................................... 3 
Figure 3 Logarithmic conductivity levels of some metals and conducting polymers .................. 4 
Figure 4 Y2K Nobel laureates: Alan J. Heeger, Alan G. MacDiarmid and Hideki Shirakawa.... 6 
Figure 5 Different applications of conducting polymers as flexible OLED display, solar cell and 
organic thin-film transistor ............................................................................................... 7 
 
Figure 6 Polyacetylene synthesis by using Ziegler-Natta catalyst................................................ 9 
Figure 7 Free-standing polyacetylene film syntheses with cis- characteristics by using Ziegler-
Natta catalyst and AsF
5
 as dopant..................................................................................... 9 
 
Figure 8 Free-standing, conducting polyacetylene film syntheses with trans- characteristics by 
using Ziegler-Natta catalyst and AsF
5
 as dopant .............................................................. 9 
 
Figure 9 Free-standing polyacetylene film syntheses with cis-/trans- characteristics by using 
Ziegler-Natta catalyst and AsF
5
 as dopant...................................................................... 10 
 
Figure 10 Chemical structure of as-produced trans-polyacetylene............................................. 10 
Figure 11 A different illustration of the chemical structure of trans-polyacetylene................... 10 
Figure 12 Iodine doping process of polyacetylene ..................................................................... 11 
Figure 13 Dehydrohalogenation reaction for polyacetylene synthesis....................................... 12 
Figure 14 Chemical structure of the aniline monomer ............................................................... 14 
Figure 15 Chemical structure of polyaniline (PANI) ................................................................. 15 
Figure 16 Protonic acid and base treatments of polyaniline between its emeraldine forms....... 16 
Figure 17 Chemical structure of the thiophene monomer .......................................................... 17 
 
?
viii
Figure 18 Chemical structure of polythiophene (PTh) ............................................................... 18 
Figure 19 Chemical structure of soluble poly (3-hexylthiophene) (P3HTh).............................. 18 
Figure 20 Chemical structure of the ethylenedioxythiophene monomer.................................... 19 
Figure 21 Oxidative polymerization of EDOT in the presence of PSS ...................................... 20 
Figure 22 Chemical structure of poly (3, 4-ethylene dioxythiophene) (PEDOT) ...................... 20 
Figure 23 Chemical structure of the pyrrole monomer............................................................... 21 
Figure 24 Chemical oxidative polymerization and doping process of pyrrole........................... 22 
Figure 25 Oxidation states of pyrrole ......................................................................................... 23 
Figure 26 Chemical structure of polypyrrole (PPy).................................................................... 24 
Figure 27 Electronic energy diagrams for (a) neutral, (b) polaron, (c) bipolaron and (d) fully 
doped polyprrole (C.B.: conduction band, V.B.: valence band)..................................... 24 
 
Figure 28 Reduced (top) and the oxidized (bottom) states of polypyrrole................................. 25 
Figure 29 Electronic band structures of different materials........................................................ 28 
Figure 30 HOMO-LUMO theory in organic semiconductor polymers...................................... 28 
Figure 31 PPy granule synthesis................................................................................................. 35 
Figure 32 PPy fiber synthesis ..................................................................................................... 35 
Figure 33 PPy nanofiber/noble metal nanoparticle composite synthesis.................................... 37 
Figure 34 Microwave initiated carbonization mechanism of nanocomposites........................... 42 
Figure 35 SEM image of PPy granule (scale bar: 2?m) ............................................................. 47 
Figure 36 SEM image of PPy fiber (scale bar: 1?m) ................................................................. 48 
Figure 37 SEM image of PPy/AuCl (0.02M) nanocomposite (scale bar: 1?m)......................... 49 
Figure 38 SEM image of PPy/AuCl (0.01M) nanocomposite (scale bar: 1?m)......................... 50 
Figure 39 SEM image of PPy/AuCl (0.005M) nanocomposite (scale bar: 1?m)....................... 51 
Figure 40 SEM image of PPy/HAuCl
4
 (0.02M) nanocomposite (scale bar: 1?m)..................... 52 
ix 
?
Figure 41 SEM image of PPy/HAuCl
4
 (0.01M) nanocomposite (scale bar: 1?m)..................... 53 
Figure 42 SEM image of PPy/HAuCl
4
 (0.005M) nanocomposite (scale bar: 100nm)............... 54 
Figure 43 SEM image of PPy/PtCl
2
 (0.02M) nanocomposite (scale bar: 100nm) ..................... 55 
Figure 44 SEM image of PPy/PtCl
2
 (0.01M) nanocomposite (scale bar: 1?m) ......................... 56 
Figure 45 SEM image of PPy/PtCl
2
 (0.005M) nanocomposite (scale bar: 1?m) ....................... 57 
Figure 46 SEM image of PPy/PtCl
4
 (0.02M) nanocomposite (scale bar: 100nm) ..................... 58 
Figure 47 SEM image of PPy/PtCl
4
 (0.01M) nanocomposite (scale bar: 100nm) ..................... 59 
Figure 48 SEM image of PPy/PtCl
4
 (0.005M) nanocomposite (scale bar: 1?m) ....................... 60 
Figure 49 TEM image of PPy/PtCl
2
 (0.01M) nanocomposite (scale bar: 200nm) ..................... 64 
Figure 50 TEM image of PPy/PtCl
4
 (0.01M) nanocomposite (scale bar: 250nm) ..................... 65 
Figure 51 TEM image of PPy/PtCl
4
 (0.01M) nanocomposite (scale bar: 100nm) ..................... 66 
Figure 52 TEM image of PPy/PtCl
4
 (0.01M) nanocomposite (scale bar: 250nm) ..................... 67 
Figure 53 TGA graphics of PPy fiber and PPy granule.............................................................. 68 
Figure 54 Comparative TGA graphics of PPy fiber and PPy granule ........................................ 68 
Figure 55 Comparative TGA graphics of PPy/AuCl nanocomposite with PPy fiber and PPy 
granule............................................................................................................................. 69 
 
Figure 56 Comparative TGA graphics of PPy/HAuCl
4
 nanocomposite with PPy fiber and PPy 
granule............................................................................................................................. 70 
 
Figure 57 Comparative TGA graphics of PPy/PtCl
2
 nanocomposite with PPy fiber and PPy 
granule............................................................................................................................. 71 
 
Figure 58 Comparative TGA graphics of PPy/PtCl
4
 nanocomposite with PPy fiber and PPy 
 granule............................................................................................................................. 72 
 
Figure 59 FT-IR spectra of PPy fiber and PPy granule .............................................................. 78 
Figure 60 FT-IR spectra of PPy/AuCl and PPy/HAuCl
4
 nanocomposites ................................. 79 
Figure 61 FT-IR spectra of PPy/PtCl
2
 and PPy/PtCl
4
 nanocomposites...................................... 80 
x 
?
xi 
?
Figure 62 SEM image of microwaved PPy/AuCl nanocomposite (scale bar: 1?m) .................. 82 
Figure 63 SEM image of microwaved PPy/HAuCl
4
 nanocomposite (scale bar: 1?m) .............. 83 
Figure 64 SEM image of microwaved PPy/PtCl
2
 nanocomposite (scale bar: 1?m) .................. 84 
Figure 65 SEM image of microwaved PPy/PtCl
4
 nanocomposite (scale bar: 1?m) .................. 85 
Figure 66 Comparative TGA graphics of non-/microwaved PPy fiber and PPy granule........... 87 
Figure 67 Comparative TGA graphics of non-/microwaved PPy/AuCl with microwaved PPy 
fiber and PPy granule...................................................................................................... 88 
 
Figure 68 Comparative TGA graphics of non-/microwaved PPy/HAuCl
4
 with microwaved PPy 
fiber and PPy granule...................................................................................................... 89 
 
Figure 69 Comparative TGA graphics of non-/microwaved PPy/PtCl
4
 with microwaved PPy 
fiber and PPy granule...................................................................................................... 90 
 
Figure 70 FT-IR spectra of microwaved PPy fiber and microwaved PPy granule..................... 93 
Figure 71 FT-IR spectra of microwaved PPy/AuCl and microwaved PPy/HAuCl
4
 
nanocomposites............................................................................................................... 94 
 
Figure 72 FT-IR spectra of microwaved PPy/PtCl
2
 and microwaved PPy/PtCl
4
  
 nanocomposites............................................................................................................... 94 
 
Figure 73 Linear four probes and a representative sample bar................................................... 96 
Figure 74 CVs of pure graphite rod and PPy fiber coated graphite rod ..................................... 99 
Figure 75 CVs of PPy/PtCl
2
 (0.02M) and PPy/PtCl
2
 (0.01M) nanocomposite coated graphite  
 rods................................................................................................................................ 100 
 
Figure 76 CVs of PPy/PtCl
2
 (0.005M) and microwaved PPy/PtCl
2
 (0.01M) nanocomposite 
coated graphite rods ...................................................................................................... 101 
 
 
 
 
 
 
 
 
CHAPTER 1 
LITERATURE REVIEW 
 
1.1 Introduction 
No more than 40 years ago all carbon based polymers
1
, polyethylene, polypropylene, e.g., 
which are essentially made up of ?-bonds
2
, have traditionally been considered as insulators
2
 (due 
to the lack of mobility of created charge through given polymer backbone chains). According to 
this manner, most of the polymer applications have focused on this insulating property
2
. Because 
of their light weight
2
, greater ease of processability
2
 and shaping, polymers (plastics) started to 
shape humans? lives
3
 in a very short time by a continuous and rapid replacement over metals in 
various areas of applications, which eventually and often remarked in those days as ?from 
buckets to rockets?
2
. 
By virtue of the common respect for the insulating property and wide utilization of 
polymers (plastics) by electric industry as inactive packaging and insulating material
1
 especially 
for electricity and telephone wires? coating, at that time, the idea of making polymers to conduct 
electricity was generally considered to be absurd
1
. However, this minute inspiration has been the 
major driving force behind most of the research trials to design polymers that could fit the 
electronic applications with their conducting property
3
.      
Throughout the time, starting from this very narrow perspective
1
, in 1958 Natta et al. was 
succeeded to synthesize polyacetylene in a black powder form, much like charcoal
2
, as the first 
1 
?
conducting polymer prototype exhibiting conductivity (due to the presence of extended ?-bond 
conjugation that confers charge carrying property along the polymer backbone chain
2
) values 
between 7x10
-11
 to 7x10
-3
 S/cm (semi-conductor level)
1
. The conductivity range of the resulting 
polymer was mainly depending upon how it was processed and/or manipulated
1
. 
 
CC
CC
CC
CC
HH
HH
HH
HH
 
C
C
C
C
C
C
C
C
HHHH
HHHH
 
Figure 1 Cis- and trans- polyacetylene 
 
This discovery was remained as a laboratory curiosity
2
 for the following nine years until 
one postgraduate student of Hideki Shirakawa at the Tokyo Institute of Technology
1
 
serendipitously
2
, obtained, a lustrous metallic thin film that exactly looks like aluminum foil
2
, 
while trying to synthesize polyacetylene in 1967
1
. Because of misusing 1000 times more of 
Ziegler-Natta (AlEt
3
 ? Ti(OBu
n
)
4
) catalyst
3
, this attempt was ended up with a shiny film like this. 
The film?s conductivity range was in semi-conductor level exhibiting similar values of 
conductivity to the best of the former black powders
1
. During the couple of years after this 
attempt, a tidal wave of renewed and amplified interest
3
 in conducting polymers had enticed 
many scientists and industrialists
3
 for new developments. 
 
2 
?
 
Figure 2 Free-standing polyacetylene film 
 
Conducting polymer research made its major resurgence
2
 in the late 70?s after a trans-
pacific collaboration
2
 of scientists Hideki Shirakawa, Alan G. MacDiarmid and Alan J. Heeger. 
At that time, chemist scientists Shirakawa and MacDiarmid were focused on an ongoing research 
about the conductivity improvement of polyacetylene through a process named ?doping? which 
was also parallel to the terminology used by semi-conductor physicist Alan J. Heeger
2
.  
Eventually, they were able to increase the conductivity of polyacetylene by almost ten 
orders of magnitude
2
 between 10
-7
 to 10
3
 S/cm. In further steps, they doped (either oxidizing or 
reducing the polymer to create charge carriers) polyacetylene films by halogens
3
, iodine (I
2
)
1
 or 
arsenic pentafluoride (AsF
5
)
1
 which cause a dramatic increase in conductivity of polyacetylene 
ranging between 10
4
 to 10
5
 S/cm (compared to copper = 10
6
 S/cm)
2
. 
 
      
3 
?
 
Figure 3 Logarithmic conductivity levels of some metals and conducting polymers
1
 
   
Pioneered by the discovery of doped polyacetylene in the late 70?s a new branch of 
polymer family known as intrinsically conducting polymers
1
, electro active polymers
1
 or 
plastronics
3
 were invented like this and became a very popular field for both academic and the 
industrial sides
3
 to catalyze many new and interesting applications
3
. The intrinsic conducting 
property and the traditional ease of processing and/or fitting into complex multi-polymer 
designs
3
 are the main reasons that make this newly popularizing polymer family very promising 
for future applications. 
 
 
 
4 
?
Table 1 Number of journal articles published annually related to conducting polymers
8
 
 
 
Table 2 Scientific papers published on conducting polymers categorized into main topics
8
 
 
 
 
5 
?
     
Figure 4 Y2K Nobel laureates: Alan J. Heeger, Alan G. MacDiarmid and Hideki Shirakawa 
 
Having an extended ?-bond conjugation along their backbone chain
2
 can be considered 
both advantageous in terms of providing intrinsic electron conducting characteristic and 
disadvantageous due to having strong inter-chain interactions and finally ending up with 
insoluble and infusible characteristics
2
, for these polymers. Throughout the time, the early and 
common problems related with exhibiting unstable characteristics in doped form and the poor 
solubility of intrinsically conducting polymers were almost surmounted by different chemical 
intuitions (by lateral substituent attachment)
1
 and/or experimentation
2
. After those so-called 
modifications were made in conducting polymer structures, their properties (especially 
conductivity) did not change negatively at all
2
.  
Although this polymer family branch is in its infancy
1
, like the plastics industry in the 
30?s or 50?s, they have myriad and very significant potential areas of use
1
 such as solar cells, fuel 
cell membranes
4
, organic vapor sensors
4
, organic light emitting diodes (OLEDs), capacitors
4
 and 
building blocks for nanoelectronic devices
4
.  
 
6 
?
   
Figure 5 Different applications of conducting polymers as flexible OLED display, solar cell and 
organic thin-film transistor 
 
That is to say, one should not be considered as a daydreamer due to imagining that one 
day in close future we will all go to the beach, carrying our table sized, solar-powered, foldable 
OLED display with us to read on-line newspaper, surf the net or watch TV while we are simply 
sitting down on it
3
. 
 
Table 3 Comparison of metals, plastics and conducting polymers in different ways
5 
 Metals Plastics Conducting Polymers 
Electrical 
property 
Conductors Insulators Conductors 
Processability Difficult Easy Easy 
Optical property Colorful/shining Colorless Colorful/shining 
Others Hard/tough Soft/flexible Soft/flexible 
 
 
 
7 
?
1.2 Types of Electronic Conducting Polymers (ECPs) 
The following paragraphs of this section of thesis are mainly focused on giving 
information about different types of conducting polymers. Therefore, the major well-known 
members of electronic conducting polymer family such as polyacetylene, polypyrrole (PPy), 
polyaniline (PANI), polythiophene (PTh) with its soluble derivative poly (3-hexylthiophene) 
(P3HTh) and poly (3, 4-ethylenedioxythiophene) (PEDOT), are explained from different points 
of view; including their history of invention and methods of synthesis, their structural and 
molecular properties and the intrinsic conduction mechanism that they exhibit during their 
applications in a simple and straightforward way.  
1.2.1 Polyacetylene 
Polyacetylene has been the main subject of innumerable conducting polymer studies so 
far
3
, due to having a longer history of invention (the first reports about this polymer dates back to 
the late middle of last century
3
). This polymer possesses the simplest conjugated molecular 
framework
2
. That is why polyacetylene has been regarded as the starting point for a variety of 
research studies, especially by physics and chemistry
2
, with an emphasis on understanding the 
conducting polymers and their conduction mechanisms
2
.  
Polyacetylene yields precipitates in a form of black, air sensitive (poor environmental 
stability
2
), infusible and insoluble powders
3
, which can not be further processed out of its 
reaction media after its polymerization reaction conducted by using Ziegler-Natta catalyst [AlEt
3
 
? Ti(OPr)
4
]
3
. 
 
 
 
8 
?
 
Black colored, infusible, insoluble, 
environmentally unstable polyacetylene 
powders 
Al(Et)
3
 / Ti(OPr)
4
HH
 
 
Figure 6 Polyacetylene synthesis by using Ziegler-Natta catalyst
3
 
 
HH
          
Free-standing, 
conducting 
polyacetylene 
film (with cis- 
characteristics)
  
    
Al(Et)
3
 / Ti(OBu
n
)
4
film thickness 10
-5
? 0.5 cm 
-78?C 
Al/Ti = 3.5-4 
toluene 
     Figure 7 Free-standing polyacetylene film syntheses with cis- characteristics by using Ziegler-
Natta catalyst and AsF
5
 as dopant
3
 
 
HH
            
                                                                                              
Al(Et)
3
 / Ti(OBu
n
)
4
-78?C 
Al/Ti = 1 
toluene 
film thickness 10
-5
? 0.5 cm 
Free-standing, 
conducting 
polyacetylene 
film (with 
trans- 
characteristics) 
 
Figure 8 Free-standing, conducting polyacetylene film syntheses with trans- characteristics by 
using Ziegler-Natta catalyst and AsF
5
 as dopant
3
 
 
 
 
 
9 
?
HH
                        
film thickness 10
-5
? 0.5 cm 
Al(Et)
3
 / Ti(OBu
n
)
4
Free-standing, 
conducting 
polyacetylene 
film (with cis- 
and trans- 
characteristics) 
-78?C 
Al/Ti = 3.5-4 
Silicone oil 
 
 
Figure 9 Free-standing polyacetylene film syntheses with cis-/trans- characteristics by using 
Ziegler-Natta catalyst and AsF
5
 as dopant
3
 
 
H
C
C
H
H
C
C
H
H
C
C
H
H
C
C
H
H
C
C
H
H
C
C
H
H
C
C
H
H
C
C
H
 
Figure 10 Chemical structure of as-produced trans-polyacetylene
5
 
 
 
Figure 11 A different illustration of the chemical structure of trans-polyacetylene
5
 
 
Further polymerization attempts for polyacetylene synthesis were mainly focused on 
?doping process? which were conducted by utilizing halogens
3
, iodine (I
2
)
1
 or arsenic 
pentafluoride (AsF
5
)
1
 as the dopant for classical Ziegler-Natta [AlEt
3
 ? Ti(OBu
n
)
4
]
3
 catalyst 
reaction. As a result of doping process it became possible to produce free-standing, conducting 
polyacetylene films of up to 0.5 cm thickness
3
. 
 
10 
?
 
I
3
-
HH
I
2 
doping
Polymerization
    
H
C
C
H
H
C
C
H
H
C
C
H
H
C
H
C
C
H
H
C
C
H
H
C
C
H
H
C
I
2 
doping
 
Figure 12 Iodine doping process of polyacetylene
5
 
  
Previous study reports also claimed that when iodine (I
2
) is utilized as the dopant it 
makes possible to elevate the conductivity level of final polymers of up to 10
5
 S/cm and allows 
producing stretchable polyacetylene films
3
. During this process, halogen iodine atoms (I
2
) first of 
all attack to the one of the double bonds in polyacetylene backbone chain, then break it and 
easily grab one electron (I
3
-
) and make the other electron free (create charge) to hop along the 
adjacent double bonds in polymer backbone chain by simply delocalizing its position with the 
subsequent double bond. It is possible to obtain polyacetylene molecules with different 
morphologies such as powder, gel, spongy mass or film by simply changing the similar reaction 
conditions
3
.  
Extended ?-bond conjugated structure renders the polyacetylene insoluble, infusible and 
environmentally unstable due to the strong intermolecular chain interactions, albeit provides a 
11 
?
nice pathway for created charges better than similar type of structures. Possessing this kind of 
inherently insoluble and insoluble structure
2
 coupled with poor environmental stability
3
 makes 
polyacetylene rather unattractive for technological applications
2
 and imposes a barrier in front of 
the processability of this polymer
3
. Throughout the time, considerable amount of research effort 
has been spent to obtain processable polyacetylene structures
3
 by following different methods 
like transformation of similar structured polymers, dehydrohalogenation of poly(vinyl chloride) 
(PVC), e.g., and/or utilization of thermally convertible metal prepolymers/precursors
3
 (ROMP). 
 
                         
CC
H
X
base
CC
 
X: Halogen atom 
(Cl in this case) 
Figure 13 Dehydrohalogenation reaction for polyacetylene synthesis 
 
Drawbacks of the dehydrohalogenation reaction are; (i) short conjugated chain length 
yield, (ii) crosslink formation, and (iii) defection threat in polymer structure
3
. Advantages of the 
ROMP method are; (i) continuous solid polyacetylene film yield, (ii) controllable morphology 
range of polyacetylene from amorphous to crystalline, and (iii) stretchable film formation during 
or prior to conversion by heat
3
. As a matter of fact, none of the polyacetylene products obtained 
through these two reactions, so far, was able to exhibit better conductivity results than that of 
doped polyacetylene itself
3
. This situation, is the work underway to be solved, can be explained 
by; (i) the reduction of conjugated chain length, and (ii) the steric repulsions between adjacent 
side groups which causes polymer chains to twist during or at the end of the reactions
3
, for the 
final products. Today, ongoing research activities are still focused on to synthesize soluble, 
easily processable and highly conducting polyacetylene structures. 
12 
?
1.3 Intrinsically Conducting Polymers (ICPs) 
During the last few decades, conducting polymers have been gathering a great interest of 
academia and industry by providing the opportunity of combining the electrical properties of a 
semiconductor and metals with the traditional advantages of conventional polymers such as easy 
and low cost preparation and fabrication in the same structure
6
. Other three major advantages of 
these polymers are their flexibility, environmental stability and chemical inertness
6
.  
As it was mentioned earlier, intrinsic electronic conductivity of these polymers arises 
from the extended conjugated ?-bond structure along their backbone chain
6
. It should be kept in 
mind that conjugated organic molecules can exhibit semiconductor properties
6
 and since the 
conducting property originates from the inherent (extended conjugated ?-bond) structure of these 
polymers, they are called as intrinsically conducting polymers
6
.  These polymers cannot be 
considered apart from the polyacetylene. However, they can be specified into four major 
polymer families, namely, polyaniline (PANI), polythiophene (PTh) with its soluble derivative 
poly (3-hexylthiophene) (P3HTh), poly (3, 4-ethylenedioxythiophene) (PEDOT) and polypyrrole 
(PPy) in terms of being the technologically relevant front runners
2
.  
Intrinsically conducting polymers can be synthesized through different types of 
polymerization reactions such as chemical oxidative polymerization, electrochemical 
polymerization, photochemical polymerization, plasma polymerization and organic synthesis
4
.  
The method we followed in our study was the chemical oxidative polymerization. For 
this type of reactions, oxidants like ammonium peroxydisulfate ((NH
4
)
2
S
2
O
8
), hydrogen peroxide 
(H
2
O
2
), ferric chloride (FeCl
3
), potassium permanganate (KMnO
4
), potassium dichromate 
(K
2
Cr
2
O
7
) and potassium perchlorate (KClO
4
)?etc.
5
 are utilized to oxidize the monomer. The 
oxidation potential of these materials, which is mainly determined by the active group in their 
13 
?
molecule, is the key point for their selection and preference for the suitable polymerization 
reactions. 
In this study, to eliminate the use of those toxic oxidative agents and to be able to directly 
deposit the noble metal nanoparticles onto the conducting polymer nanostructures, different 
noble metal salts with oxidation properties such as AuCl, PtCl
2
, PtCl
4
 and HAuCl
4
.3H
2
O were 
utilized to obtain ?polypyrrole (PPy) nanofiber/Au or Pt nanoparticle? composites. 
1.3.1 Polyaniline (PANI) 
Polyaniline was invented by a German chemist, Carl Julius Fritzsche, in 1840
7
. He first 
obtained a colorless oil from indigo and called it aniline due to the similarity of these two 
materials in appearance and then oxidized this oil to polyaniline (PANI)
7
. Since this invention, 
polyaniline has attracted lots of scientists? attention and made them to investigate this polymer 
largely from different points of view. 
 
NH
2
?
Figure 14 Chemical structure of the aniline monomer 
 
To obtain polyaniline from the aniline monomer, the most widely employed synthetic 
routes are the chemical oxidative polymerization and the electrochemical (constant voltage, 
constant current, sweeping voltage methods) polymerization
3
. Besides these two routes; the 
interfacial polymerization, electro spinning, seeding polymerization and the template 
polymerization methods are also commonly used to produce nanostructured polyaniline
7
.  
14 
?
Chemical oxidative polymerization (radical cationic) reaction of aniline is usually 
conducted in acidic medium with a suitable oxidizing agent such as APS ((NH
4
)
2
S
2
O
8
) and 
proceeds to form polyaniline. As-produced polyaniline can be rendered electrically conducting 
by an additional acid treatment (doping) after its polymerization reaction.  
Polyaniline has a rather unique polymeric structure which is mainly composed of 
sequentially alternating benzene rings and nitrogen atoms
2
. The existence of nitrogen atoms as 
imine (in sp
2
 hybridized state) or amine (in sp
3
 hybridized state) forms
2
, and their relative 
proportion in the overall polymer backbone chain determines the resulting structure and the 
different properties of polyaniline.  
There are four well-known forms of polyaniline available in the literature according to 
their reduced/oxidized repeating unit proportions
2
. Different oxidation states of polyaniline can 
be obtained by using previously mentioned oxidants like iodine (I
2
), but the resulting 
conductivity of these structures is less than that are obtained by acid doping
3
. 
 
 
Figure 15 Chemical structure of polyaniline (PANI)
5
 
 
Leucoemeraldine is the fully reduced state of polyaniline. This type of polyaniline has a 
pale brown color and does not exhibit conducting property
2
. The emeraldine state of polyaniline 
does not have conducting property either and can be differentiated with its blue color. On the 
other hand, the only electronic conducting state of polyaniline is the protonated emeraldine form 
which has partially oxidized/reduced structure. Conductive property of this state originates from 
15 
?
the protonated charge carriers that are generated after the acid treatment of the emeraldine form 
(reversible reaction by base treatment)
2
. This state of polyaniline has a dark green color, a 
versatile solid structure that is insoluble, infusible and intractable
7
 in organic solvents and a 
conductivity value between 2-10 S/cm. In contrast to this form, emeraldine polyaniline can be 
dissolved in N-methyl pyrrolidone (NMP) or dimethyl sulfoxide (DMSO) solvents and has a 
processable characteristic with a conductivity value of 10
-10
 S/cm
7
.The fully oxidized state of 
polyaniline with its pink/purple color is called pernigraniline. In contrast to the most of the 
similar polyaromatics, pernigraniline state of the polyaniline does not exhibit conducting 
property like the others do
3
 in its fully oxidized state.  
Conductivity of the polymer is mainly affected by the impurities (water and dopant 
content) in its structure
3
. For example, completely dry polymers exhibit five times less 
conductivity than the ones containing some water in their structure. Similarly, polymers with 
more dopant content have higher conductivity than the pure ones
3
.  
  
N
H
N
H
N
H
N
H
Cl
Cl
x
0.1 M NH
4
OH
N
H
N
H
NN
x
0.1 M HCl
?
Figure 16 Protonic acid and base treatments of polyaniline between its emeraldine forms
7
 
 
16 
?
Polyaniline itself has some unique properties such as wide and controllable range of 
conductivity, yielding intrinsic fibrillar morphology, and melt or solution processable property 
that are superior to other conducting polymers
7
. This polymer can be used as the conductive 
compound for different blends with conventional polymers like polystyrene
7
. Also polyaniline 
plays an important role as the processing aid material by providing conductivity for its various 
reactions
7
. Another important application area of polyaniline is the use of this polymer to 
produce colored or transparency conductive products
7
. 
1.3.2 Polythiophene (PTh) and Poly (3-hexylthiophene) (P3HTh) 
The earliest research studies about the synthesis and/or the different properties of 
polythiophene are dating back to thirty years ago. This polymer can be prepared through similar 
synthetic approaches as those (chemical oxidative polymerization, electrochemical 
polymerization?etc.) described for polyaniline
3
. 
?
S
?
Figure 17 Chemical structure of the thiophene monomer 
 
Polymerization reaction of thiophene takes place by following almost the same way of 
polyaniline and finally, polythiophene structure is obtained by the coupling of chains propagated 
during the reaction and the loss of two protons from their structure at each step. In further steps 
polythiophene can be doped by using different acids or dopants like FeCl
3 
to render the polymer 
electrically conducting. This polymer also has a rigid polymer backbone structure that can not be 
dissolved in organic solvents like many other linear polyaromatic compounds
3
. 
17 
?
 
Figure 18 Chemical structure of polythiophene (PTh)
5
 
 
However, by lateral substitution group attachments at the 3-position (prevents the 
crystallization of conjugated polymer backbone chain), solubility and the processability of the 
structure can be enhanced
7
 and a more soluble form of this polymer, namely, poly(3-
hexylthiophene) (P3HTh) with its long alkyl side chain groups can be obtained
2
. 
 
 
Figure 19 Chemical structure of soluble poly(3-hexylthiophene) (P3HTh)
2
 
 
Electrochemical polymerization method is also commonly utilized for thiophene to 
prepare thin conducting films with controlled thicknesses
3
. Likewise the other conducting 
polymers
7
 polythiophene (PTh) also have various popular and interesting areas of use such as 
18 
?
light emitting diodes, corrosion protection of metals, non-linear optical devices, sensors for 
volatile organic materials and organic solar cells.  
1.3.3 Poly (3, 4-ethylenedioxythiophene) (PEDOT)  
One of the most popular members of the conducting polymer family is PEDOT with its 
uniquely combined conductive and optical properties that have been largely investigated in 
recent years by the academia and intentionally by the different areas of industry to build a better 
knowledge for the future studies and applications of this polymer like organic light emitting 
diodes, flat panel displays and as semiconductor for organic transistors.  
  
OO
S
?
Figure 20 Chemical structure of the ethylenedioxythiophene monomer 
 
19 
?
 
Fe
2
(SO
4
)
3 
Na
2
S
2
O
8
 
(Polystyrene 
sulfonic adic-
PSS) 
Figure 21 Oxidative polymerization of EDOT in the presence of PSS
7
 
 
Chemical oxidative polymerization is the most commonly used method to synthesize this 
polymer out of EDOT
7
. A well-known polymerization reaction takes place in the presence of 
EDOT monomer, polystyrene sulfonic acid (PSS) and a suitable oxidant like iron(III)sulfate 
(Fe
2
(SO
4
)
3
) by resulting a polymer complex of two ionomers called PEDOT:PSS.  
 
 
Figure 22 Chemical structure of poly (3, 4-ethylenedioxythiophene) (PEDOT)
5
 
20 
?
This final polymer mixture is one of the most popular industrial outcomes of PEDOT 
which is utilized for different applications mentioned above. Excellent transparent and optical 
properties in hand, PEDOT also exhibit good electrical conductivity (due to its low band gap) 
within its environmentally stable structure. Unfortunately this polymer is also insoluble in 
organic solvents like its big brothers, which makes it hard to process during its revolutionary 
applications. 
1.3.4 Polypyrrole (PPy) 
Polypyrrole is one of the most widely studied members of intrinsic conducting polymer 
family in different areas of science and industry. The first solid information about the 
conductivity level of iodine doped, chemically oxidized polypyrrole is dating back to 1963 (DE 
Weiss et.al.)
7
. 
 
N
H
?
Figure 23 Chemical structure of the pyrrole monomer 
 
With this information in hand, polypyrrole can be considered as the first derivative of 
polyacetylene that exhibits a high level of conductivity. Throughout the time polypyrrole 
research has been extended to the very different parts of chemistry and polymer science to gain a 
deeper knowledge and to improve different properties of this polymer for further applications.  
 
21 
?
N
H
-e
-
N
H
N
H
N
H
N
H
+
N
H
H
N
-2H
+
N
H
H
N
H
HH
H
H
H
N
N
H
H
N
Cl
-
x
?
Figure 24 Chemical oxidative polymerization and doping process of pyrrole
7 
 
The most common methods applied to synthesize polypyrrole are the chemical oxidative 
polymerization with doping, electrochemical polymerization, plasma polymerization and the 
organic synthesis. Chemical oxidative polymerization of pyrrole monomer is very similar to that 
of thiophene
3
 with one distinct difference that should be kept in mind during the reaction which 
related to the reactive nitrogen-hydrogen bond
3
. Due to this reactive bond in its structure, 
protection of amine is required to prevent undesired side reactions to take place such as 
crosslinking
3
.  
General mechanism of the oxidative polymerization of pyrrole can be briefly explained in 
the following way. Formation of cationic free radicals after the loss of an electron from the 
monomer structure is followed by the coupling of active resonance structures in different 
positions during the reaction (oxidation of monomer, radical-radical coupling). These already 
22 
?
coupled structures finally form the polypyrrole chain at the end of the polymerization reaction 
(deprotonation, re-aromatization and chain propagation). 
 
 Figure 25 Oxidation states of pyrrole
8
 
 
The traditional conjugated ?-bond backbone structure of polypyrrole usually is not 
enough to possess significant conductivity on its own
9
. The conductivity level of this polymer 
can remarkably be changed from an insulating level to a metallic one through the doping 
process
9
. That is why the partial charge extraction (doping) process is required and can be 
explained for this polymer in the following way.  
Again, first of all, an electron is removed from the polymer backbone by yielding a 
radical and a spinless positive charge
1
. Next, the newly formed cation and the radical are coupled 
to each other by local resonance
1
. During coupling, quinoid-like sequential rings are also formed 
and utilized to provide higher energy of distortion than the remaining part of the chain
1
. The 
created lattice distortion is usually extended over four pyrrole rings (charged site) and when they 
coupled with a radical, this structure is called polaron
1
. As a result, further oxidation of the 
polaron yields a new spinless defect called bipolaron having a lower energy than two distinct 
polarons
1
. At higher doping levels, polarons are eventually replaced by bipolarons
1
. For a heavily 
doped polypyrrole it is suggested that the upper and lower bipolarons merge to the valence and 
23 
?
conduction bands respectively to produce partially filled bands and provide metallic-like 
conductivity for the final polymer
1
. 
 
 
Figure 26 Chemical structure of polypyrrole (PPy)
5
 
 
 
(a)                       (b)        (c)     (d) 
Figure 27 Electronic energy diagrams for (a) neutral, (b) polaron, (c) bipolaron and (d) fully 
doped polyprrole (C.B.: conduction band, V.B.: valence band)
9
 
 
24 
?
Polypyrrole also has an insoluble and intractable conjugated polymer backbone chain 
similar to the other members of this family. However, in different reports so far it has been 
reported that it is possible to synthesize soluble polypyrrole structures by using alcohol or 
organic solvent soluble dopants with long alkyl chains like sodium bis(2-ethylhexyl) 
sulfosuccinate (C
20
H
37
NaO
7
S)
8
.   
Exhibiting conductivity values
5
 between 10-50 S/cm polypyrrole has been verily utilized 
in different types of scientific/industrial applications such as electrodes for rechargeable batteries 
and supercapacitors, electromagnetic shielding materials, actuators, electrochromic devices and 
membranes, corrosion protecting materials and fuel-cell membranes
7
. It is also possible to 
process different kinds of conventional polymers with polypyrrole while they are still in solution 
or melt forms
8
. 
 
 
Figure 28 Reduced (top) and the oxidized (bottom) states of polypyrrole
8
 
 
25 
?
Due to providing unique and tunable physicochemical and conductivity properties as well 
as better environmental stability and advantageous higher surface area for various applications, 
nanostructured polypyrrole has also gained a great prominence throughout the different studies
4, 
10-12
 so far and became one of the major inspirations of this study too. 
 
Table 4 Different attributes of ICPs
1
 
Conducting Polymer Conductivity 
(1/?.cm) 
Stability 
(doped state) 
Processability 
Polyacetylene 10
3
 - 10
5
 Poor  Limited 
Polyaniline 1-10 Good  Good  
Polythiophene 10-50 Good  Excellent  
Poly(3, 4-
ethylenedioxythiophene) 
10-50 Good  Excellent  
Polypyrrole 10-50 Good  Good  
 
1.4 Theory of Conductivity and the Conduction Mechanism of Conducting Polymers 
The electronic conducting property and conduction mechanism of these polymers have 
been the key point and/or major inspiration for both their first discovery and for many researches 
on conducting polymers throughout the time. As it was mentioned frequently in various points of 
this study, also, the electronic conductivity is the most important property of conducting 
polymers than any others they possess. This very significant property of conducting polymers 
can be explained in a simple and straightforward way by the HOMO-LUMO (band gap) theory
5
.  
26 
?
According to this theory, to obtain higher conductivity in organic semiconductors; longer, 
conjugated ?-bond backbone structure is required. Therefore, lower energy will be enough for 
charges to move through the bands with less energy difference. In other words, the energy 
difference between the lowest unoccupied molecular orbital (conduction band) and the highest 
occupied molecular orbital (valence band) will be lower as the conjugated ?-bond structure gets 
longer for these polymers.  
The intrinsic conjugated polymer backbone structure, which provides a pathway for free 
charges to move through the polymer backbone chain by a sequential delocalization with ?-
bonds (hopping) under an applied electric field or during the doping process, is the main reason 
of conducting property of these polymers. Then it becomes possible to claim that the overall 
conducting property depends on two components; (i) intrachain mobility, which corresponds to 
the charge transfer along the polymer backbone chain and (ii) interchain mobility which involves 
the hopping or tunneling of the created charge from a bond to neighboring bonds
9
.  
The final conductivity of a polymer is controlled by the combination of these two types
9
 
of mobility. Conformational and chemical defects (distorted conjugated structure) in polymer 
backbone, which should be kept in mind and taken care of during polymerization, can restrict the 
intrachain mobility
9
. Therefore, to be able to achieve higher electrical conductivities in 
conducting polymers the mobility of the charge carriers should be improved
9
 through the 
effectively controlled polymerizations of these structures. 
 
27 
?
. 
Figure 29 Electronic band structures of different materials
5
 
 
 
LUMO 
HOMO 
Figure 30 HOMO-LUMO theory in organic semiconductor polymers
5
 
 
 
28 
?
 
 
 
CHAPTER 2 
SYNTHESIS OF CONDUCTING POLYMER/NOBLE METAL PARTICLE 
NANOCOMPOSITES 
 
2.1 Introduction 
Since MacDiarmid and his co-workers? first successfully synthesis of the highly 
conductive polyacetylene film through iodine (I
2
) doping process
2
 in 1977, studies focused on 
the intrinsically conducting polymers has shown a tremendous increase during the last few 
decades. Owing to their relatively easy preparation, high levels of conductivity, tunable 
physicochemical properties and morphologies with good environmental stability
13
, the synthesis 
of intrinsically conducting polymers and their nano-sized composites, which are playing vital 
roles (by providing higher surface area and superior electron transfer performances) in 
determining material properties
12
 that are obtained through various academic and industrial 
applications, has received a wide-spread interest
10
 throughout the time. Most of the potential 
scientific and commercial applications like nanoelectronics
12
 devices, light emitting diodes
10
, 
volatile organic gas sensors
14
, biosensors
14
, capacitors
14
 and catalysts
14
 e.g. of the nano-sized 
versions of conducting polymers are highly benefiting these unique properties that they 
intrinsically provide.  
In particular, due to its uniqueness among the intrinsically conducting polymers
13
 with its 
high conductivity at physiological pH
11
, easy preparation
12
, environmentally stable structure
12
 
29 
?
and promising potential for future applications
12
 polypyrrole (PPy) was selected to be 
synthesized in its nanofiber form for this study. Despite several methods that have been 
developed or utilized to synthesize polypyrrole with different properties and morphologies, the 
shape-depending synthesis and properties of this polymer was rarely discussed
12
.  
Overall reports, so far, indicate the need of different kinds of ?seed templates? to ensure 
the synthesis and growth of nanofiber formed polypyrrole
12
. Fibrillar growth is an intrinsic 
property of another conducting polymer polyaniline (PANI)
12
. It has been proved that an added 
seed template into the reaction media orchestrates
11
 the synthetic route along the pre-existing 
pathways of polyaniline, however, in polypyrrole system these pathways have to be induced by 
using either seed templates that are self-reactive toward the pyrrole monomer or those that can be 
rendered reactive
12
, if not, PPy with only spherical morphology can be obtained
12
.  
The bulk synthesis of PPy nanofibers, directly from its monomer, having fiber diameters 
in nanoscale has been reported as a challenge for several studies that attempted to try and achieve 
this within the pores of different in/soluble templates such as zeolite, alumina or on the surface 
of nanostructured templates
11
. Some previous methods like surfactant-mediated synthesis, 
interfacial synthesis and nanofiber seeding?etc.
11
 were, again, successful in the synthesis of 
PANI nanofibers, however, they were only able to yield nanofibrous or granular powders of 
PPy
11
. The only observation of PPy nanofibers or nanotubes could be possible when the large 
organic dopant anions such as naphthalene sulfonic acid were used during reactions
11
. These so-
called nanofibers or tubes were seemingly formed as a result of the solution aggregation of the 
dopant anions and presented a wide range of diameters changing between 50-2000nm
11
.  
As an attempt to surmount this key synthetic challenge in the control of nanofibrillar 
morphology of polypyrrole, in this study, a novel ?seeding approach? that utilizes an oxidative-
30 
?
reactive and degradable
13
 seeding template (vanadium pentoxide, V
2
O
5
 sol-gel nanofibers) which 
can chemically react with the pyrrole monomers prior to the addition of oxidant
11
, was described.  
The reaction that takes place on the surface of the fibrillar V
2
O
5
 seeding templates 
enables to manage the evolution of bulk nanofibrillar morphology before the oxidant is 
subsequently added to the reaction media
11
. It is not possible to obtain any fibrillar morphology 
if a passive or an inert seed is used for such reactions
11
. Unlike the previously described template 
directed methods
11
 only a catalytic amount of seeding template was used for this study
11
. Other 
than V
2
O
5
, a variety of in/organic and biological seeding templates such as ~50nm diameter 
polyaniline nanofibers
15
, ~20nm diameter single-wall carbon nanotube (SWCNT) bundles 
obtained from HiPco route
15
 and ~12nm diameter nanofibrous hexapeptide (a seed in the 
polymerization of Alzheimer?s disease tau protein)
15
?etc. were also utilized for similar type of 
reactions in previous studies. 
As it was postulated in a former study that
15
 regardless of the diversity in different 
synthetic approaches about this topic, the remarkable change in polymer morphology is 
originating from a mechanism explained as; polymeric nanostructures presenting at the very 
early stages of a polymerization reaction can direct the bulk formation of similar nanostructures. 
In this study, also consistent with the above mechanism, bulk polypyrrole nanofibers which were 
obtained through a polymerization reaction was seeded at the very early stages by a very small 
amount of nanofibers (independently from their chemical nature), were instantiated
15
. 
In short, nanofibrillar morphology can only be observed in such systems which the 
seeding template used must; (i) itself provide nanofibrillar morphology and (ii) also be oxidative-
reactive with the monomer
11
. 
31 
?
Potential advantages of incorporating noble metal nanoparticles into conducting polymers 
have gained great prominence in recent years; with most of these can be considered initial 
reports focusing on gold
10
. In a previous study, gold nanoparticles were modified with 
flourophores to generate an effective route for improved optoelectronic applications
10
. Other than 
that in another study a significant problem of charge recombination, which often restricts the 
charge separation performances in donor-acceptor systems, was overcame with the presence of 
gold nanocores which can quench the excited states of polymer and remarkably enhance the 
overall performance
10
. It was mentioned in one previous work that the use of gold nanoparticles 
was also improved the performance of light emitting diodes and efficient memory devices
12
 with 
the power conversion efficiency of solar cells
10
 and the sensitivity of chemical sensors
12
.  
Recently, benefits of using aqueous solutions of noble metal salts as the growth media for 
conducting polymers have also attracted increasing attention
10
. Utilization of this kind of 
solutions is (one of the key points of this study) getting increasingly preferable over volatile 
molecular solvents for wide-spread synthetic and device applications
10
 because of providing 
advantageous properties like eliminating the production of toxic vapors during reactions, 
improving the performance and lifetimes of conducting polymers that are used as supporting 
surfaces, eliminating the use of toxic oxidative agents like APS [(NH
4
)
2
S
2
O
8
] or in/soluble 
templates that are used for conventional oxidative polymerization of conducting polymers, and 
allowing to work at potentials that were previously prohibited by the smaller electrochemical 
window of molecular solvent/electrolyte systems
10
.    
The synthesis and characterization of nanocomposites of intrinsically conducting 
polymers with the noble metal nanoparticles was the main topic and the goal of this study by 
reason of its cruciality that originates from the potential that was readily provided by combining 
32 
?
two frontier technologies in one structure to yield materials with great academic and industrial 
interest gathering properties
10
, which would be fuelling a drive towards promising future 
applications
10
.  
Via a novel, facile and one-step chemical oxidative polymerization reaction, which was 
assisted by self-degrading, self-oxidative-reactive seeding template V
2
O
5
 sol-gel nanofibers, of 
pyrrole monomers, conducting polymer (polypyrrole-PPy) nanofibers containing noble metal 
(Au or Pt) nanoparticles that were in-situ deposited through a spontaneous redox reaction with 
PPy
12
, were synthesized. During the following paragraphs of this chapter the experimental 
method, that was followed for this novel approach, in different concentrated variant aqueous 
solutions of the previously mentioned noble metal salts such as AuCl, PtCl
2
, PtCl
4
 and 
HAuCl
4
.3H
2
O without the need for any toxic oxidative agents, in/soluble templates and/or 
capping agents, was explained in details. 
2.2 Experimental Section 
2.2.1 Materials 
For polypyrrole fiber, granule, nanocomposite and carbon nanotube (CNT) synthesis; 
pyrrole (98+%), gold (I) chloride (AuCl)Au 84.2% min., platinum (II) chloride (PtCl
2
) 98%, 
hydrogen tetrachloroaurate (III) hydrate (HAuCl
4
.3H
2
O) Au 49% min., platinum (IV) chloride 
(PtCl
4
) Pt 57.9% min. and ammonium peroxydisulfate (APS (NH
4
)
2
S
2
O
8
) 98% were all 
purchased from Alfa Aesar and used as received.  
Also, ammonium metavanadate (NH
4
VO
3
) 99.5% from ACROS ORGANICS and 
DOWEX
? 
MARATHON (H) ion-exchange resin from Sigma Aldrich were purchased to prepare
 
V
2
O
5
 sol-gel nanofibers within Deionized (DI) water, according to a process which was 
33 
?
explained earlier
11
 (in 160mL DI water + 0.8g NH
4
VO
3
 + 8g Dowex resin were mixed together 
without shaking or magnetic stirring).  
For the purification of final polymeric and nanocomposite structures; acetone (BDH
?
) 
(CH
3
)
2
CO was purchased from VWR and used with DI water. 
For the electrochemical (cyclic voltametry, CV) and different characterization 
applications of polymeric and nanocomposite structures of PPy; potassium hydroxide (KOH) 
pellets from SPECTRUM, methanol (BDH
?
) CH
3
OH from VWR, ethyl alcohol pure 200 proof 
(CH
3
CH
2
OH) from EMD, graphite rods (6.15mm diameter, 152mm length and 99.9995% metal 
basis) from Alfa Aesar and colloidal graphite (isopropanol base) as EM science brand product 
from VWR were all purchased and used without further purification. 
2.2.2 Synthesis Methods 
2.2.2.1 Synthesis of Polypyrrole (PPy) Granules and Fibers 
Two different PPy structures having granular and fibrillar morphologies were prepared as 
control samples for the nanocomposite structures whose preparation will be explained in the 
following parts of this section.  
Granular PPy preparation can be explained as; in 60mL DI water, 1mL of pyrrole was 
gently added under magnetic stirring. This mixture was stirred for the following 5-10min. to 
obtain a better dispersion of pyrrole in DI water. At the end, 1.15g of APS was added into the 
solution by changing its color from light yellow to black with the spontaneous formation of PPy 
structures dispersed into the solution.  
Fibrillar PPy preparation can be explained as; in 60mL of DI water, 1mL of V
2
O
5 
sol-gel 
nanofibers was firstly added under magnetic stirring. The addition of 1mL pyrrole monomers 
into this solution should be completed in 20-60sec. after V
2
O
5
, to initiate and maintain the 
34 
?
fibrillar structure formation for resulting PPy molecules. Finally, 1.15g of APS was added into 
the reaction media, by changing its greenish yellow color to black, to initiate the polymerization 
of pyrrole. Both solutions were magnetic stirred for the following 4-5 hours to obtain better 
polymerization of so-called structures. 
 
??????
N
H
?? ????? ?? ? ??????
Pyrrole (1mL) 
APS (1.15g) 
Magnetic Stir 4-5 hrs. 
DI water (50mL)  
 
Figure 31 PPy granule synthesis 
 
     
N
H
?? ?????? ????? ?? ?
V
2
O
5
 sol-gel (1mL) 
Pyrrole (1mL) 
APS (1.15g) 
Magnetic Stir 4-5 hrs. 
DI water (50mL)  
 
Figure 32 PPy fiber synthesis 
 
2.2.2.2 Preparation of Standard Aqueous Noble Metal Salt Solutions 
The standard concentration was 0.02M for the aqueous electrolyte solutions of different 
metal salts. 0.001mole of each noble metal salt (0.266g of PtCl
2
, 0.337g of PtCl
4
, 0.232g of AuCl 
and 0.394g of HAuCl
4
.3H
2
O) were weighed and then dissolved in 50mL of DI water in 
35 
?
individual beakers under continuous magnetic stirring to obtain better homogeneity. The solutio
color was changed from transparent to light yellow, yellow, dark yellow and pale brown (after 
AuCl, HAuCl
4
.3H
2
O, PtCl
4
 and PtCl
2 
additio
n 
ns, respectively) in each beaker with the dissolved 
noble m
on 
s diluted in 37.5mL DI water to 
2.2.2.3 s    
haped conducting polymers (PPy) that were decorated with noble metal 
nanopa
rs was 
 
e 
ery 
etal salts? particles floating into it.  
These standard solutions were later used to prepare control electrolyte solutions of same 
salts with different concentrations (0.01M and 0.005M) to unveil the effect of concentration on 
the final product morphology and other properties. The control electrolyte solutions? preparati
can be explained as; 25mL of 0.02M electrolyte solution was diluted in 25mL of DI water to 
obtain 0.01M concentration, and 12.5mL of 0.02M solution wa
obtain 0.005M concentration to obtain same amounts (50mL). 
 Synthesis of Polypyrrole (PPy) Nanofiber/Noble Metal Nanoparticle Composite
To the best of our knowledge, this type of one step, self-oxidative-reactive and self-
degrading seeding template (V
2
O
5
 sol-gel nanofibers) assisted oxidative polymerization of 
pyrrole monomers, was the first attempt that has ever been made to obtain nanocomposites 
composed of nanofiber s
rticles (Au, Pt).  
The method followed can be simply explained as; 1mL of V
2
O
5
 sol-gel nanofibe
gently added into the readily prepared, different concentrated aqueous noble metal salt 
electrolyte solutions (reaction media) under magnetic stirring by changing the solution color into
greenish yellow. Here, one key point that should be kept in mind is about the length of the tim
gap between the sequential addition of V
2
O
5
 and the pyrrole monomer, which should be v
small. In order to initiate and maintain the nanofiber formation for the resulting polymer 
structures, the addition of monomer to the reaction media should be completed within 20-60sec. 
36 
?
after the V
2
O
5
. Next, 0.1mL of pyrrole monomers were added subsequently to the reaction media 
by obeying the above mentioned rule. The solution color was spontaneously darkened and turned
into black with the formation and dispersion of black precipitates of PPy into the reaction media
as a result of oxidation and/or polymerization of pyrrole initiated by the noble metal salts. T
reaction solution was magnetic stirred for the following 24 hours for better distribu
 
 
he 
tion of 
onducting polymer nanocomposites and noble metal nanoparticles among them. 
 
c
N
H
? ? ???? ????? ?
 
Figure 33 PPy nanofiber/noble metal nanoparticle composite synthesis 
2.2.2.4
 
e 
 
 
? ? ??
 
 Purification of As-prepared Samples 
At the end of the specific polymerization times (4-5 hours for PPy granule and fiber and 
24 hours for the nanocomposite samples) all different types of reaction solutions containing the
black precipitates of polymeric structures and/or nanocomposites were gone through the sam
purification process. Each and every prepared sample was washed and suction filtered, in a 
Whatman 70mm diameter filter paper equipped
16
 Buchner funnel, which was attached to a water 
respirator, by using copious amounts of DI water (3x100mL) -to remove the residual monomers
and its water soluble decomposition by products with the oxidant- and Acetone (3x100mL) -to
remove low molecular weight organic intermediates and oligomers
17
- from the system and to 
DI water (50mL)  
V
2
O
5
 sol-gel (1mL) 
Pyrrole (0.1mL) 
Noble metal salt (0.001mol) 
Magnetic Stir 24 hrs. 
37 
?
facilitate the drying process of the as-prepared samples with the quick evaporation of aceton
The wet dark blue or dark brown precipitates were allowed air drying (5
e. 
-10min.) inside the 
funnel 
 
d the 
s obtained from different electrolyte solutions were 
summarized in the following table. 
able 5 Amounts of the nanoco yields obtained f erent noble metal salt solutions 
 0.02M 
until there was no more liquid left to suck from the filter paper.  
Next, the filter paper was taken out of the funnel and stored at standard laboratory
conditions overnight for a complete evaporation and drying. At the following day, dried 
precipitates of polymeric structures and nanocomposites were finally collected from the filter 
paper surface, then weighed and stored in different glass vials with correct labeling for further 
characterization steps. The average yields of PPy fiber and granules were both ~0.41g an
average yields of the nanocomposite
 
T mposite rom diff
0.01M 0.005M 
AuCl/PPy 0.0698g 0.0431g 0.0061g 
HAu Py Cl
4
.3H
2
O/P 0.2975g 0.1685g 0.0421g 
PtCl
2
/PPy 0.2032g 0.0811g 0.0336g 
PtCl
4
/PPy 0.2425g 0.1663g 0.0741g 
 
2.2.3 Preparation of Electrolytes for the Cyclic Voltammetry (CV) Applications and 
Electro
e 
us 
chemical Characterization 
For the electrochemical methanol (CH
3
OH) oxidation reaction, catalyzed by the nobl
metal particles in as-prepared nanocomposites, through cyclic voltammetry (CV) of readily 
prepared PPy fiber and nanocomposite samples with noble metal nanoparticles, 1M aqueo
38 
?
KOH solution was prepared by first of all weighing ~56.1g (1mol) of KOH pellets, then 
dissolving them into 1L volumetric flask filled with DI water under magnetic stirring. 80m
KOH+CH
3
OH solution was prepared by mixing 76mL of 1M aq. KOH + 4mL methanol 
respectively in same beaker and used as the electr
L of 
olyte for the electrochemical application and 
2.2.4 P
 
orous salt bridge
35
), which were readily prepared by Zhen Liu, used as the 
2.2.5 M
vert 
e surfaces decorated with noble metal nanoparticles into 
carbon 
 
utilized as the composite additive to enhance the several properties and also the conductivity of 
characterizations of above mentioned samples.   
reparation of Electrodes for the Cyclic Voltammetry (CV) Applications 
Besides these electrolytes, graphite rods and colloidal graphite were utilized to prepare
electrodes for so-called applications. Graphite rods were modified to decrease the amount of 
surface and material amount interacting with the alligator clips and the electrolyte solutions. At 
the effective tips of the graphite rods (working electrode) which were placed into the electrolyte, 
colloidal graphite was applied to be able to paste as-prepared polymeric and nanocomposite 
samples. Another pure graphite rod with sharpened tips was used as counter electrode vs. SCE 
(saturated calomel electrode -a saturated solution of potassium chloride [KCl] in water linked to 
the electrolyte via a p
reference electrode. 
icrowave Initiated Carbonization of Nanocomposite Samples 
The major goal of this subsection was to investigate another novel nanoengineering 
technique, which had already been proposed for a different, previous research study
18
, to con
conductive polymer nanocomposit
nanocomposites (CNCs).  
Higher surface area of CNCs provides remarkable advantages for the processability and
the applications of the material. That is why these kinds of carbon nanocomposites are widely 
39 
?
different structures. Despite these superior merits, this research has also some challenges in 
terms of the areas of design, synthesis and instrumentation. 
Various conventional techniques that require high temperature and high energy density 
for extended periods of time and also the use of inorganic templates, were commonly used to 
obtain nanocarbon products. The main common challenges of these conventional production 
methods and nanocarbon material itself can be summarized as; (i) the requirement of an inert gas 
protection, complicated instrumentation, long periods of high energy density, insoluble template 
use (and additional removal steps for these templates) (ii) and the lack of capability for the bulk 
synthesis of such structures from lab scale to industrial level.  
As an attempt to address the challenges mentioned so far; a novel and high scale 
production capable microwave approach
18
 was developed to synthesize CNC materials. By using 
microwave irradiation such composite materials with tunable and beneficial properties like 
catalysis ability, can be manufactured by remaining their original morphologies.  
Before the performance of this novel technique to the nanocomposite materials, the 
interactions between microwave irradiation and different types of (conductor, insulator) 
materials should be understood carefully. Here, the key property of different materials which 
plays a vital role to understand this interaction is the conductivity. The experimental data up to 
date indicates that materials within moderate conductivity (intrinsically conducting polymers) 
levels from 10
-5
 to 10?.m can be heated more efficiently than insulating or highly conductive 
materials.  
Another important property that affects the performance of the microwave treatment is 
the dimensions of the material. Since, in most cases, good and thick conductors are readily able 
to reflect the microwave irradiation and thin ones have a lot less capabilities; nanostructured 
40 
?
conducting polymers with moderate conductivity can absorb microwave energy in a very 
efficient way which makes them promising outcomes of the rapid CNC production 
applications
18
. In view of the fact that a huge amount of heat can be generated by microwave 
treatment of conducting polymers, they can readily be used as sacrificial precursor matrixes to 
support their conversion to CNCs. 
This novel method to produce CNCs requires more simplified setups than conventional 
ones. Basically, a microwave oven and glass vials are more than enough to conduct this energy 
efficient method that eliminates especially the cumbersome template removal step of the 
conventional approaches. The cost of resulting CNCs from this method is also much lower than 
any other existing approaches. The production volume of CNCs can be readily scaled up to large 
amounts, which is required for the applications in different areas, such as the infrastructure and 
composite materials? production due to their high demand every year.  
For this application 50mg or 100mg of each polymeric and nanocomposite structure was 
prepared in solid state and placed into glass vials. As-prepared solid samples were exposed to 
microwave irradiation for a very short time (30s to 1min.; depending on the reactivity of the 
material) at, usually, highest energy level (1250W) to convert their PPy nanofiber matrixes into 
CNCs. During microwave irradiation, the conducting polymer matrix absorbs the energy, and its 
temperature increases rapidly (continuous flames and sparks were observed during applications) 
which was high enough to convert PPy nanofiber molecules into carbon.  
 
41 
?
?   
Carbon nanocomposites 
decorated with Au/Pt 
nanoparticles (with 
remained nanofiber 
morphology) 
As-prepared PPy 
nanofibers decorated with 
Au/Pt nanoparticles 
Microwave 
Irradiation
Figure 34 Microwave initiated carbonization mechanism of nanocomposites 
 
Care should be taken, in case of explosion of glass vials due to the rapid increase of 
temperature and pressure inside them, during the applications. Finally, CNC samples exhibiting 
similar fibrillar morphology were collected and stored carefully for further characterization 
studies. To investigate the morphology and other property changes, after microwave treatment, 
of selected nanocomposite samples various characterization tests were applied and the obtained 
results were discussed in the following chapter of this study. 
2.2.6 Instruments and Characterization Methods 
Thermogravimetric Analysis (TGA); a TA Instruments TGA Q500 thermogravimetric 
analyzer was used to characterize the thermal properties of PPy structures with different 
morphologies (PPy fibers/granules and nanocomposites decorated with different noble metal 
nanoparticles and CNT samples obtained from microwave treatment). ~5mg of each sample was 
exposed to thermal heating under pressurized air, from room temperature to 800?C at 10?C/min 
rate.   
Scanning Electron Microscopy (SEM); a Zeiss EVO 50 variable pressure scanning 
electron microscope with digital imaging and EDS, was used to characterize the morphological 
properties of very small pieces of above mentioned samples. An EMS 550X auto sputter coating 
42 
?
device with carbon coating attachment was also utilized for gold sputtering of samples, which 
were readily prepared on carbon tape mounted sample holders, before testing them at SEM. 
Transmission Electron Microscopy (TEM); a Zeiss EM 10C 10CR transmission electron 
microscope was used for a more detailed morphological characterization. Different 
nanocomposite samples were dispersed homogenously in ethyl alcohol, then transferred (~5?L) 
onto a carbon coated aluminum Formvar grid and left drying at standard laboratory conditions 
before TEM testing. 
Electrochemical Cyclic Voltammetry (CV); voltammetric data of four different samples 
(PPy fiber, PPy/PtCl
2
 0.02M, PPy/PtCl
2
 0.01M, PPy/PtCl
2
 0.005M and microwaved PPy/PtCl
2
 
0.01M) were recorded at standard laboratory conditions by an Arbin electrochemical instrument 
(Arbin-010 MITS Pro 4-BT 2000). Tests were conducted by applying -0.8V to 0.4V vs. SCE at 
20mV/s to the so-called samples coated electrodes in KOH+CH
3
OH electrolyte, according to the 
way described earlier. 
Fourier Transform Infrared (FT-IR) Spectroscopy; all the IR Transmittance spectra were 
recorded by a Thermo Fischer Scientific NICOLET 6700 FT-IR instrument. This device uses an 
attenuated total reflectance (ATR) module that collects IR spectra independently from sample 
size and without any further sample preparation requirement for solid and liquid samples, 
between wave number ranges of 400cm
-1
 to 4000cm
-1
. 
Elemental Analysis; weight %s of C, N, O, Cl, V, Au, Pt elements within each as-
prepared nanocomposite were measured by Oxford Instruments, INCA EDX instrument to 
verify and determine the exact chemical formulas of the sample products obtained. 
4-Probe Conductivity Measurement; was performed by following a linear four probe 
method that was described in a previous study
19
 of our group. Four probes were connected to 
43 
?
Agilent Technologies 34980 multifunctional switch & measure unit which was applying an 
adjusted potential to the sample that was interacting with the four probes. As-prepared 
nanocomposites and different morphology PPy structures were initially and individually 
pressed under 3500psi in a mold cavity to form a thin film, and then four probes were touched 
onto this thin film to measure the specific resistance. Measurement results and calculations 
about the conductivity values of each sample were given and explained in the following 
chapter. 
   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
44 
?
 
 
 
CHAPTER 3 
RESULTS AND DISCUSSIONS 
 
3.1 Introduction 
A novel, facile, one-step chemical oxidative polymerization of pyrrole monomers, which 
was assisted by self-degrading and oxidative-reactive seeding templates (V
2
O
5
 sol-gel 
nanofibers), to synthesize nanostructured composite materials that were composed of conducting 
polymer (PPy) nanofibers decorated with in-situ deposited noble metal (Au, Pt) nanoparticles, 
was described in details. Besides this novel method, conventional syntheses of conducting 
polymers (PPy) with different morphologies (fiber, granule) were also explained as the control 
mechanisms.  
All different samples obtained through these experiments were characterized through 
different perspectives by using various polymer characterization techniques to build a substantial 
knowledge for the promising future applications of these structures. Characterization results 
collected during the tests and applications mentioned at the previous chapter of so-called 
polymeric structures were discussed in a detailed and comprehensive manner along the following 
sections of this chapter.   
Inspired from a previously described ?nanofiber seeding? approach
15
 this method?s 
novelty originates from its ?in/soluble template and toxic, inorganic oxidative agent free? 
synthesis route that utilizes various aqueous noble metal salt solutions as the reaction media and 
45 
?
the oxidative agent with self-degrading, oxidative-reactive V
2
O
5
 sol-gel nanofibers as the 
seeding template. It was also postulated, according to the previously inspired ?nanofiber 
seeding? approach, in this study that the underlying reason of conducting polymer nanofiber 
formation was mainly due to the addition of nanofiber seeding templates (V
2
O
5
 sol-gel in both 
cases) at the very early stages of the chemical oxidative reaction of pyrrole monomers. This early 
addition before the oxidant was considered to be the reason to initiate and guarantee the bulk 
formation of similar morphology structures during the polymerization reaction as a result of a 
surface interaction (pre-polymerization) between pyrrole and the seeding template. That is why 
this approach was called ?nanofiber seeding?
17
. 
3.2 Different Characterization and Application Results and Discussions 
3.2.1 SEM Characterization Results 
Different morphology conducting PPy structures (granules and fibers) were initially 
characterized by SEM to verify and prove the success of above mentioned, seeding-template-
assisted (V
2
O
5
 sol-gel nanofibers) chemical oxidative polymerization approach in aqueous 
media.  
In PPy granule sample?s SEM image below, the characteristic spherical formation of PPy 
molecule aggregates was clearly been exhibited. By the initial addition of V
2
O
5 
sol-gel 
nanofibers, before the pyrrole monomers and oxidant, to the reaction media let this chemical to 
generate and maintain the formation of similar structures like itself through a spontaneous pre-
polymerization that took place at the interface created between these nanofibers and pyrrole 
monomers. Thus, when the oxidant, APS, was added to the reaction solution it could initiate the 
formation of PPy fibers through a rapid oxidation polymerization reaction which was already 
assisted by V
2
O
5 
sol-gel nanofibers. PPy fibers that were obtained through a same kind of 
46 
?
polymerization reaction, exhibiting the dominant fibrillar morphology through its overall matrix 
structure, could clearly be observed from the second SEM image below.  
 
 
Figure 35 SEM image of PPy granule (scale bar: 2?m) 
 
In conclusion, the success of early mentioned novel, one-step, seeding-template-assisted 
oxidative polymerization reaction of pyrrole monomers under the control of V
2
O
5
 sol-gel 
nanofibers has simply been verified through the morphological analysis of same polymers? 
differently shaped structures, by SEM. By the initial addition of so-called seeding templates to 
47 
?
the reaction media before the monomer and oxidative agent, similar morphology (fibrillar) 
polymeric structure formations were offered and guaranteed through this approach. 
  
 
Figure 36 SEM image of PPy fiber (scale bar: 1?m) 
 
As it can clearly be seen from the following SEM images of as prepared nanocomposite 
samples below, the method followed to obtain nanocomposites (PPy nanofibers that were 
decorated with noble metal nanoparticles) was also successful. Ten different measurements taken 
from the arbitrary points of each and every SEM image of nanocomposite structures clearly 
48 
?
proved that there was a very high yield of uniform diameter conducting polymer nanofibers with 
well dispersed, different sized noble metal nanoparticle particle aggregates among them. 
  
 
Figure 37 SEM image of PPy/AuCl (0.02M) nanocomposite (scale bar: 1?m) 
 
For the nanocomposites obtained from different concentrated AuCl salt solutions (0.02M, 
0.01M and 0.005M) the SEM images were indicating uniformly dispersed and smooth 
conducting polymer nanofibers having average diameters of 50nm, 50nm and 55nm, 
respectively. Aggregations of mostly spherical noble metal nanoparticles having several hundred 
nm average sizes (580nm, 255nm, and 677.5nm, respectively) could also clearly be observed 
49 
?
from those images. The aggregation and dispersion of the noble metal nanoparticles was more 
uniform at nanocomposite samples obtained from 0.02M solution, but more obvious and 
dominant at samples obtained from 0.005M solution.  
 
  
Figure 38 SEM image of PPy/AuCl (0.01M) nanocomposite (scale bar: 1?m) 
 
This was probably related with the changing reaction solution concentrations. Fewer 
amounts of the noble metal particle nuclei that were ubiquitous in the lowest concentrated noble 
metal salt solution could not be dispersed and induced through conducting polymer nanofibers 
during the polymerization reaction. The interactions between different concentrated noble metal 
50 
?
salt solutions and conducting polymer nanofibers could clearly be observed from different SEM 
images below, according to the final morphologies of the nanocomposite structures.  
 
 
Figure 39 SEM image of PPy/AuCl (0.005M) nanocomposite (scale bar: 1?m) 
 
Reactions in higher concentrated solutions tend to produce longer, thinner and smoother 
nanofibers of PPy. In such reactions, the resulting PPy nanofibers were utilized to fabricate noble 
metal nanoparticles via in-situ deposition
12
. Thus, if the solution concentration is higher, then it 
becomes easier to form nanofibers (with the higher oxidation potential of the solution) that can 
manipulate the dispersion and dimensions of the metal nanoparticles and their aggregates.     
51 
?
?
Figure 40 SEM image of PPy/HAuCl
4
 (0.02M) nanocomposite (scale bar: 1?m) 
 
In contrast, when a lower concentrated noble metal salt solution was used for 
polymerization then the resulting nanofibers became shorter in length, thicker in diameter and 
less effective for manipulating the dispersion and dimensions of the noble metal nanoparticles. 
 
52 
?
?
Figure 41 SEM image of PPy/HAuCl
4
 (0.01M) nanocomposite (scale bar: 1?m) 
 
Nanocomposites obtained from different concentrated HAuCl
4
.3H
2
O salt solutions were 
exhibiting unique stereoscopic
12
 web-like structures. These structures were obtained a result of a 
uniform nanofiber dispersion that was coating the surface of the aggregated noble metal 
nanoparticles. It was really hard to point these aggregates within the nanocomposite structures. 
They could barely be located by just visualizing their irregular solid morphologies under the 
web-like nanofibers. 
 
53 
?
  
Figure 42 SEM image of PPy/HAuCl
4
 (0.005M) nanocomposite (scale bar: 100nm) 
 
The same, uniform fiber diameter dispersion was also dominant for these nanocomposites 
like in PPy/AuCl ones. According to the arbitrary measurements taken from the SEM images of 
these nanostructures; average nanofiber diameters were 27nm, 25nm and 23nm for the metal salt 
solution concentrations of 0.02M, 0.01M and 0.005M, respectively. 
 
54 
?
?
Figure 43 SEM image of PPy/PtCl
2
 (0.02M) nanocomposite (scale bar: 100nm) 
 
As the solution concentration was decreased, obtained nanofiber diameters were also 
decreased by remaining their web-like structures for these nanocomposites. Then it became 
much easier to locate the noble metal nanoparticle aggregates within the nanocomposite 
structures.  
 
55 
?
?
Figure 44 SEM image of PPy/PtCl
2
 (0.01M) nanocomposite (scale bar: 1?m) 
 
The dispersion of noble metal nanoparticle aggregates were seemed to be more uniform 
in nanocomposite structures obtained from less concentrated solutions. The average sizes of such 
structures were 507nm, 446nm and 193nm, respectively for the samples from 0.02M, 0.01M and 
0.005M noble metal salt solutions. 
In contrast to its higher concentrated versions, it was possible to easily observe a fewer 
amount of aggregated noble metal nanoparticles in the nanocomposite structure obtained from 
0.005M noble metal salt solution which was also exhibiting an obvious, uniform and traditional 
web-like nanofiber formation.  
56 
?
?
Figure 45 SEM image of PPy/PtCl
2
 (0.005M) nanocomposite (scale bar: 1?m) 
 
Here, according to a general phenomenon, one key property that determined the final 
morphology of the conducting polymer nanofibers and aggregated noble metal nanoparticles was 
the reduction/oxidation potential relationship of both sides.  
 
57 
?
?
Figure 46 SEM image of PPy/PtCl
4
 (0.02M) nanocomposite (scale bar: 100nm) 
 
The oxidation potential provided by the noble metal salts was utilized to initiate the 
polymerization of pyrrole. Likewise, the reduction potential provided by the conducting polymer 
(PPy) supplies the necessary electrons to reduce the noble metal ions to particles, through a 
nucleation reaction. Therefore, the redox potential of the conducting polymer must be negative 
of the standard potential of the noble metal complex
14
 or vice versa. 
 
58 
?
?
Figure 47 SEM image of PPy/PtCl
4
 (0.01M) nanocomposite (scale bar: 100nm) 
 
Similarly to the previous structures, PPy/PtCl
2
 nanocomposites were also exhibiting a 
very dense nanofiber formation and hardly defined noble metal nanoparticle aggregations 
(almost impossible to locate). For the highest concentrated noble metal salt solution, the 
nanocomposite sample obtained was composed of obvious -but not uniform- and irregularly 
shaped nanofibers that were covering the hidden noble metal nanoparticles whose surface could 
barely be seen as silhouettes by shining brighter than the nanocomposite matrix. 
 
59 
?
?
Figure 48 SEM image of PPy/PtCl
4
 (0.005M) nanocomposite (scale bar: 1?m) 
 
As the solution concentration was decreased to 0.01M a remarkable change in the 
nanocomposite morphology was observed. Both nanofibers and noble metal nanoparticle 
aggregates in this structure became more regular and obvious. The dense, web-like characteristic 
of the nanocomposite matrix left its place to the individual, wrinkled nanofibers and mostly 
spherical shaped noble metal nanoparticles. 
The main reason of this change in the nanocomposite morphology was believed to be 
directly related with the previously mentioned phenomenon about the red./ox. potentials. At 
higher concentrations (0.02M) the oxidation potential was also high, that is why monomers were 
60 
?
tending to form bulk and dense, web-like nanofiber structures when they were added to the 
reaction media under the control of nanofiber seeding templates. At moderate concentrations 
(0.01M) the oxidation potential was decreased and more balanced formation and distribution of 
nanofiber structures could be obtained.  
However, at low concentrations (0.005M), sometimes the oxidation potential of the 
solution does not enough to trigger the polymerization reaction to produce nanofibers, as it could 
clearly be seen from the SEM image. For this nanocomposite, the matrix structure was composed 
of irregular shaped and uniformly dispersed conducting polymer nanostructures that were 
covering the mostly spherical shaped noble metal nanoparticle aggregates whose surface 
silhouettes could be observed on and under the nanocomposite matrix. On the average, 
conducting polymer nanostructures (fibers, particles) having 23nm, 26nm and 70nm diameters 
and 261nm, 276nm and 847nm surface areas were detected at the SEM images of 
nanocomposites obtained from three different concentrated noble metal salt solutions of PtCl
2
. 
When the SEM images of the nanocomposites obtained from three different PtCl
4 
salt 
solutions were investigated; the similar web-like and dense nanofiber formation was clearly 
observed for higher concentration (0.02M). Nanofiber formation was uniform and composed of 
continuous long fibers, which were mostly stacked together, with the average diameters of 21nm. 
Noble metal nanoparticle aggregates with 98nm average sizes and uniform spherical 
morphologies were well dispersed among those nanofibers.  
As the noble metal salt solution concentration was decreased to 0.01M there was an 
increasing trend observed for the formation of irregularly shaped and more stacked nanofibers. It 
was hard to define certain diameter values for these nanofibers but they were obviously thicker 
than the previous ones (averagely ~24nm). However, the noble metal nanoparticles with 
61 
?
spherical shapes were still well dispersed among these nanofibers. Their sizes were slightly 
larger than the previous ones (~103nm).  
In contrast, nanocomposites from the lowest concentration (0.005M) solution were 
exhibiting more individualized nanofiber formation rather than web-like with larger diameters of 
~74nm. However, these nanofibers were not seemed solid like the ones from higher concentrated 
solutions. It was postulated that this situation was again directly related with the redox 
phenomenon mentioned before. The lower oxidation potential of lower concentrated noble metal 
salt solution could barely trigger the polymerization of pyrrole and caused to form this type of 
individual nanofibers that were not solid and not stacked together. Noble metal nanoparticle 
aggregations were again well dispersed among those nanofibers by exhibiting mostly spherical 
morphologies in a wide range of particle sizes (~770nm average). ?
Morphologically controlled, bulk PPy nanofibers? and different noble metals? 
nanoparticle aggregations formation were explained, according to the SEM images of 
nanocomposite samples obtained from different concentrated noble metal salt solutions, through 
the oxidation/reduction phenomenon and the interactions between the two major compounds of 
these structures.  
In summary, the overall SEM characterization of as-prepared nanocomposites was 
conforming the success of the mechanism of this novel, one-step, and nanofiber seeding-
template-assisted chemical oxidative polymerization of pyrrole monomers in different aqueous 
noble metal salt solutions to obtain PPy nanofibers that were decorated with noble metal 
nanoparticles. The phenomenon of controlling the morphology of conducting polymers from 
nanospheres to nanofibers, and also the size of the noble metal nanoparticle aggregates was 
accomplished by changing the noble metal salt (oxidative agent and dopant) solution 
62 
?
concentrations and by using seeding templates exhibiting the targeted morphology, in such 
reactions. 
3.2.2 TEM Characterization Results 
To be able to obtain advanced morphological characterization results of different 
nanocomposite structures and to verify the noble metal aggregations within them; additional 
TEM images, which were taken with PPy/PtCl
2
 and PPy/PtCl
4
 nanocomposites obtained from 
0.01M reaction solutions, were utilized due to their better representation of nanocomposite 
structures.  
According to the TEM image of PPy/PtCl
2
 (0.01M) nanocomposite; the web-like, dense 
nanofiber formation among the irregularly shaped noble metal nanoparticle aggregates was 
clearly observed. Long and individual nanofibers could also easily be noticed besides their 
traditional web-like formation. These two general results were matching the ones obtained from 
the SEM characterization of the same nanocomposite samples. Even very small sized noble 
metal nanoparticles (whose surfaces could only be visualized as silhouettes in the SEM images) 
that were aggregated among the densely packed nanofibers, could clearly be seen in the TEM 
images below.  
    
63 
?
 
Figure 49 TEM image of PPy/PtCl
2
 (0.01M) nanocomposite (scale bar: 200nm) 
 
Secondly, the TEM images taken from the PPy/PtCl
4
 nanocomposites were investigated 
to be able to understand the morphological characteristics of the nanocomposite structure better. 
The images were clearly exhibiting the individual rod-like nanofiber formations that were 
uniformly dispersed among the irregularly aggregated noble metal nanoparticles in different 
sizes.  
 
64 
?
 
Figure 50 TEM image of PPy/PtCl
4
 (0.01M) nanocomposite (scale bar: 250nm) 
 
The TEM images of the same nanocomposite structure that were taken at higher 
magnifications were helped to comprehend the morphological properties better. Uniform and 
individual nanofibers that were stacked together among the aggregated, mostly spherical, noble 
metal nanoparticles could clearly be observed from the TEM image below. 
 
65 
?
 
Figure 51 TEM image of PPy/PtCl
4
 (0.01M) nanocomposite (scale bar: 100nm) 
 
Similar morphological characteristics of the same nanocomposite structure was 
represented, in a more compatible manner by benefiting the measurements taken from the TEM 
images, at the higher magnification TEM image below. As a result of their web-like stacking 
characteristics conducting polymer nanofibers were filling the spaces between the noble metal 
nanoparticles that were composed of mostly spherical aggregates in different sizes.  
 
66 
?
 
Figure 52 TEM image of PPy/PtCl
4
 (0.01M) nanocomposite (scale bar: 250nm) 
 
It can be summarized, according to the arbitrary measurements taken from the TEM 
images of different nanocomposites, that the SEM and TEM results were compatible and 
complementary for each other in terms of nanofiber formation, diameter and the noble metal 
nanoparticle dimensions for different nanocomposite structures. 
3.2.3 TGA Characterization Results 
Albeit the TEM characterization could offer a very detailed information about the overall 
morphological properties of the as-prepared nanocomposites, this technique still could not able 
to quantify the bulk noble metal nanoparticles that were located widespread in the 
67 
?
nanocomposite structure
10
. Therefore, in order to quantify those noble metal nanoparticles? 
content in each and every nanocomposite structure, thermal characterization was applied by 
using the TGA instrument in a way that was described earlier. 
 
  
Figure 53 TGA graphics of PPy fiber and PPy granule 
 
 
Figure 54 Comparative TGA graphics of PPy fiber and PPy granule 
 
68 
?
As the control data to be compared with the nanocomposite structures? thermal 
characterization, PPy fiber and granule samples were also utilized for this study. All the collected 
thermal characterization results were explained in a comparative way and in details through the 
following paragraphs of this section. 
The first TGA results obtained from the control samples of PPy fiber and granule, 
respectively. So-called graphics were following a very similar trend with slight differences in 
their thermal stability and decomposition temperature values. According to the TGA graphic of 
PPy fiber represented with black color, ~12% of the sample weight was lost during the initial 
heating between the beginning temperature to 100?C, which was supposed to be the weight of the 
moisture that was stored within the polymeric structure. Decomposition of the sample was 
started around 250?C and the sample weight was steadily decreased as the temperature was 
increased up to 600?C. 
 
   
Figure 55 Comparative TGA graphics of PPy/AuCl nanocomposite with PPy fiber and PPy 
granule 
 
69 
?
The major weight loss from the sample (~88%) was observed between the temperatures 
of 200?C to 600?C (averagely from 315?C to 539?C). Finally, there was no sample left in the 
TGA pan and the weight % reading from the graphic was showing zero. 
When the TGA graphic obtained from the PPy granules (represented with dashed red 
color) was investigated, less amount of weight loss (~11%) was observed at the beginning, 
between the initial temperature to 100?C. It was probably because of the less humidity that was 
stored within the smaller surface area of PPy granule molecules than fibers. The sample weight 
became constant for a little while between the temperatures of 100?C to 250?C, and then the 
structure started losing weight at a higher rate than the PPy fiber sample, upon futher heating. 
 
  
Figure 56 Comparative TGA graphics of PPy/HAuCl
4
 nanocomposite with PPy fiber and PPy 
granule 
 
From 200?C to 700?C, 89% of the sample weight was gone because of this quick 
decomposition, between the average temperatures of 260?C to 573?C, took place. Finally, same 
as the PPy fiber, the PPy granule sample?s weight % was also reached to zero at the end of the 
70 
?
experiment. By comparing the final decomposition temperatures they last and their rates of 
decomposition, it could be summarized from these two different morphology polymeric 
structures? thermal characterization results that PPy fiber samples were exhibiting less thermal 
stability  than the PPy granule samples. 
After the thermal characterization of PPy fiber and granule samples, each and every 
nanocomposite obtained from standard (0.02M) noble metal salt solutions was also thermally 
characterized in a comparative way with these two different morphology PPy structures.  
 
  
Figure 57 Comparative TGA graphics of PPy/PtCl
2
 nanocomposite with PPy fiber and PPy 
granule 
 
First of all, the TGA graphic of the nanocomposite sample obtained from AuCl salt, 
represented with green color, was investigated. According to the graphic, 2.5% of the sample 
weight was lost from the beginning temperature up to 100?C indicating the less amount of 
moisture stored within the structure, than the previous polymeric samples. Supposedly, as a 
result of the PPy nanofibers characteristic in the nanocompsite structure, this sample started 
71 
?
being decomposed between a temperature range from 200?C to 250?C. Between 100?C to 
600?C, especially during the range between 407?C to 555?C,  the major weight loss from the 
nanocomposite sample was observed (28.7%). Finally, the sample weight became constant after 
600?C and the leftover weight %, which was believed to be belong to the Au nanoparticles, was 
showing (~70%) in the TGA pan. 
Secondly, when the TGA graphic obtained from the PPy/HAuCl
4
 nanocomposite was 
investigated, initially there was a weight loss of ~3.7% from the sample was observed, due to the 
moisture within the structure. Around 250?C the sample started being decomposed and exhibited 
a linear and more stable weight loss than the AuCl nanocomposite until 700?C where the weight 
% value became constant after all. The major weight loss (31.5%) was observed between the 
temperature values of 345?C to 645?C. Finally, ~65% of the nanocomposite weight was 
remained in the TGA pan which was indicating the weight % of Au nanoparticles in the 
structure. 
 
  
Figure 58 Comparative TGA graphics of PPy/PtCl
4
 nanocomposite with PPy fiber and PPy 
granule 
72 
?
After gold nanocomposites, the ones obtained from the platinum salts were thermally  
characterized at TGA. According to the results of PPy/PtCl
2
 nanocomposite, there was only 1.2% 
of the weight was lost at the very beginning because of the moisture inside the sample. Then the 
sample was started slightly being decomposed around 200?C and exhibited a sharp weight loss 
(mainly between 377?C to 452?C) of 29.5% until 500?C where the residual weight of the sample 
became constant. Similarly to the AuCl nanocomposite, this one had also ~70% residual weight 
of metal nanoparticles within its structure. 
The last nanocomposite sample characterized at TGA was from PtCl
4
. The experimental 
data was showing a 7.2% of weight loss from the nanocomposite until 100?C due to the moisture 
content. A bigger weight loss -than the PtCl
2
 sample- of ~44.6% took place between 100?C to 
500?C and the nanocomposite weight became constant, finally at that temperature. The residual 
metal nanoparticle amount in this structure was 48% according to final readings from the TGA 
graphic.   
In summary, the previously mentioned, one-step, novel synthesis method of conducting 
polymer nanocomposites within the noble metal salt solutions through a chemical oxidative 
polymerization reaction of pyrrole was successfully achieved high loading amounts of metal 
nanoparticles onto PPy nanofibers changing in a range of 48% to 70% based on the affinity and 
electrochemical interactions between these two compounds. According to the overall TGA data 
(especially from gold samples) that were indicating higher initial and final decomposition 
temperatures for nanocomposite structures, it could be suggested that the incorporation of noble 
metal particles into PPy nanofibers improved their thermal properties and provide more stable 
characteristics for the nanocomposite structures.     
 
73 
?
3.2.4 EDX Analysis Results 
Although, the thermal characterization was applied to obtain more detailed information 
about the incorporation of noble metal nanoparticles within the nanocomposite structures after 
the microscopical analysis, a series of supplementary elemental analysis were also conducted 
sequentially by using all different types of nanocomposites to acquire the most accurate 
proportions of each different element in nanocomposites.  
Despite the EDX is a surface technique, it has a deep penetration depth from the material 
surface
10
 to the measurement point selected inside the structure and can provide more accurate 
results than the bulk thermal analysis which differs averagely 12.5-31% higher from the EDX 
results (due to the unburned metal/carbine structures).  
Seven different arbitrary measurements were taken from the different points of each and 
every nanocomposite surface, and then the distributions of different elements within the 
structures were recorded sequentially. The overall results of seven measurements taken from all 
different nanocomposite structures, obtained from three different concentrated noble metal salt 
solutions, were listed in the following table. According to the analysis results, the average 
distribution of noble metals (Au and Pt) in different nanocomposites were in the range of 35% to 
55% -mainly around 40%- of the total nanocomposite weight. 
Based on the elemental analysis results represented below, the exact chemical formulas 
of one nanocomposite structure selected from each different metal salt solutions were 
determined. Here, since the materials were mounted on a carbon tape, the C% obtained from the 
EDX characterization may vary (instrument might have also considered the carbon molecules in 
the tape while taking the measurements) that is why the N% values were taken as the 
representative for the PPy part of the chemical structure of the nanocomposites.  
74 
?
Table 6 Summary of the EDX analysis results of all different nanocomposite structures 
Sample C N O Cl V Au / Pt Total 
PPy/AuCl 
0.01M 
36.59 9.17 5.44 0.97 -0.17 47.99 100 
PPy/AuCl 
0.02M 
30.26 8.69 4.03 1.80 0.07 55.14 100 
PPy/AuCl 
0.005M 
34.98 9.93 4.96 0.69 -0.10 49.54 100 
PPy/HAuCl
4
 
0.01M 
39.26 10.09 2.89 2.35 0.24 45.17 100 
PPy/HAuCl
4
 
0.02M 
43.45 9.05 4.92 4.48 -0.02 38.14 100 
PPy/HAuCl
4
 
0.005M 
43.42 14.50 5.08 2.00 0.16 34.83 100 
PPy/PtCl
2
 
0.01M 
29.42 5.91 9.10 11.07 2.75 41.76 100 
PPy/PtCl
2
 
0.02M 
27.79 4.96 5.28 12.86 0.93 48.18 100 
PPy/PtCl
2
 
0.005M 
32.44 6.73 10.78 8.61 6.22 35.21 100 
PPy/PtCl
4
 
0.01M 
38.24 5.38 5.45 9.06 0.20 41.68 100 
PPy/PtCl
4
 
0.02M 
33.34 9.16 5.31 9.99 0.20 41.99 100 
PPy/PtCl
4
 
0.005M 
34.39 6.37 7.19 9.37 0.18 42.50 100 
 
Similarly, since H% could not be measured by EDX, to be able to represent the H
2
O part 
of the chemical formulas, O% values were used. Selected nanocomposite samples were 
75 
?
PPy/AuCl (0.02M), PPy/HAuCl
4 
(0.01M), PPy/PtCl
2
 (0.02M) and PPy/PtCl
4
 (0.02M). First of 
all, weight % values of C, N, O, Cl, Au and Pt of each selected nanocomposite sample were 
divided by the molecular weights of those elements. Next, the reciprocal values of calculated N 
amounts were taken as the constant to complete other amounts to 1 or 100%.  
After all calculations made, the standard chemical formulas of the nanocomposites were 
represented as; (PPy)(Cl)(H
2
O)(Au or Pt). Chemical formulas of selected nanocomposites were 
listed according to the calculations as; (PPy)(Cl)
0.08
(H
2
O)
0.406
(Au)
0.451
, 
(PPy)(Cl)
0.09
(H
2
O)
0.251
(Au)
0.318
, (PPy)(Cl)
1.022
(H
2
O)
0.93
(Pt)
0.697
, (PPy)(Cl)
0.43
(H
2
O)
0.51
(Pt)
0.329
, 
respectively for the so-called nanocomposites mentioned above. Same calculations were also 
made for the microwaved versions of the same samples and the results were discussed in the 
following paragraphs of this chapter. 
Stable dispersions of the noble metal nanoparticles, which was very size dependent, 
among the conducting polymer nanofibers was achieved through this novel, one-step, seeding-
template-assisted chemical oxidative polymerization reaction of pyrrole. EDX results were also 
consistently unveiling the proportional relation between the noble metal salt solution 
concentrations and the noble metal nanoparticle ratios in nanocomposites for almost every 
sample.  
Another important information obtained from this analysis was about the fate of the 
seeding template, V
2
O
5
 nanofibers. The residual % amounts of V element in nanocomposite 
structures were showing consistency with the previous study results
11
 and were almost zero for 
especially the ones obtained from Au salt solutions. This was actually indicating the advantage 
of  the universal seeding template approach followed for the synthesis of nanocomposites. By 
using very little amounts (1-3mg) of V
2
O
5
 nanofibers in reactions it was possible to obtain bulk 
76 
?
amounts of nanofibers at the end which were almost free of V (even though the residual V was 
washed away at the purification step). The ascending V% amount ranking in nanocomposite 
structures was listed as AuCl, HAuCl
4
, PtCl
4
 and PtCl
2
, respectively.  
As a result, it could be suggested that during the reaction the seeding template was 
quantitatively removed from the final structure without any additional template removal step 
requirement
11
 by following the two possible pathways which were (i) reacting with the pyrrole 
monomer, and (ii) being dissolved and washed away in H
2
O
11
. 
3.2.5 FT-IR Characterization Results 
To be another complementary and/or supplementary study for EDX and to prove the 
overall success of our novel, one-step, seeding-template-assisted chemical oxidative 
polymerization of pyrrole within different concentrated noble metal salt solutions to synthesize 
conducting polymer nanocomposites decorated with noble metal nanoparticles, additional FT-IR 
spectroscopy characterizations were applied to all different polymeric and standard (0.02M) 
nanocomposite structures obtained.  
Very similar results, with some slight shiftings and intensity differences in peaks, were 
obtained from the FT-IR characterization of two different mophology structures of PPy. 
According to the FT-IR spectrum of PPy fiber (represented with black color) several well-known 
PPy peaks were clearly observed at the corresponding wave numbers of 2733.3cm
-1
 (C-H 
stretching vibrations), 1540.1cm
-1
 (C-C and C=C stretching vibrations), 1446.1cm
-1
 (C-N 
stretching), 1294.9cm
-1
, 1160 cm
-1
, and 1021.1cm
-1
 (C-H and C-H in plane deformation modes) 
and finally 878.1cm
-1
, 771.9cm
-1
 and 657.4cm
-1
 (C-H outer bending vibrations). 
 
77 
?
  
Figure 59 FT-IR spectra of PPy fiber and PPy granule 
 
Likewise, the PPy granule sample was exhibiting very similar FT-IR peaks in its 
spectrum (represented with red color), by slightly shifting towards shorter wavelengths, at 
corresponding wave numbers of 2708.7cm
-1
 (C-H stretching vibrations), 1536cm
-1
 (C-C and 
C=C stretching vibrations), 1446.1 (C-N stretching), 1290.8cm
-1
, 1156cm
-1
, and 1012.9cm
-1
 (C-
H and C-H in-plane deformation modes) and finally 882.2cm
-1
 and 706.5cm
-1
 (C-H outer 
bending vibrations). 
FT-IR spectra of the nanocomposites obtained from two different Au salts? standard 
solutions (0.02M) were both exhibiting smooth and similar graphics whose peak locations were 
also in a good agreement with the PPy nanofiber characteristics in their structures. The major 
FT-IR peaks of both Au nanocomposites, especially the ones from AuCl, were located at shorter 
wavelengths than the different polymeric PPy structure peaks, supposedly due to the higher 
oxidation of PPy with the ions from AuCl, at the corresponding wave numbers of 1503.3cm
-1
 (C-
C and C=C stretching vibrations), 1278.5cm
-1
 (bipolaron band of PPy in doped state), 1147.8cm
-
78 
?
1
 (C-N stretching), 1004.8cm
-1
 (C-H in-plane deformation), and finally 886.3cm
-1
 and 706.5cm
-1
 
(C-H outer bending vibrations). 
 
  
Figure 60 FT-IR spectra of PPy/AuCl and PPy/HAuCl
4
 nanocomposites 
 
FT-IR spectrum of the nanocompostite obtained from HAuCl
4
 salt solution (represented 
in blue color) were also exhibiting almost identically located peaks with AuCl ones, which were 
slightly shifted to longer wavelengths at the corresponding wave numbers of 1540.1cm
-1
 (C-C 
and C=C stretching vibrations), 1450.2cm
-1
 (C-H in-plane deformation), 1274.5cm
-1
 (bipolaron 
band of PPy in doped state), 1156cm
-1
 (C-N stretching), 1017cm
-1
 (C-H in-plane deformation), 
886.3cm
-1
 (C-H outer bending vibration) and finally 759.6cm
-1
 (C-H out-of-plane deformation). 
FT-IR spectra of the nanocomposites obtained from different Pt salt solutions were quite 
different from the previously explained ones in terms of peak intensity. However, both spectra of 
so-called nanocomposites were still exhibiting the characteristic peaks of PPy consistently due to 
the PPy nanofibers in their structures. 
79 
?
 The major peaks in the FT-IR spectrum of PtCl
2
 nanocomposite were listed as the 
following; at the corresponding wave numbers of 3284.9cm
-1
 (N-H stretch vibration), 1683.1cm
-1
 
(C=C out-of-plane bending), 1589.1cm
-1
 (PPy ring vibration), 1331.7cm
-1
 (=C-H in-plane 
vibration), 1282.6cm
-1
 (bipolaron PPy band in doped state), 1180.5cm
-1
 (C-N stretching), 
1049.7cm
-1
 (C-N vibration) and finally at 939.4cm
-1
 (=C-H out-of-plane bending). 
 
  
Figure 61 FT-IR spectra of PPy/PtCl
2
 and PPy/PtCl
4
 nanocomposites 
 
When the FT-IR spectrum of nanocomposite obtained from PtCl
4
 salt solution was 
investigated, a clear observation of increased intensity and slight shiftings of characteristic peaks 
to shorter wave lengths could be made. Detected characteristic peaks were listed in the following 
sequence at corresponding wave numbers of; 3227.7cm
-1
 (N-H asymmetric stretching), 
3113.3cm
-1
 (little shoulder at the peak represents again N-H stretching), 1560.5cm
-1
 (PPy ring 
stretching), 1454.3cm
-1
 (PPy ring vibration), 1331.7cm
-1
 (=C-H in-plane vibration), 1180.5cm
-1
 
(C-N stretching), 1045.6cm
-1
 (C-N vibration), 923cm
-1
 (C-H bending) and finally at 784.1cm
-1
 
(C=C out-of-plane bending). 
80 
?
In summary, the FT-IR characterization of different morphology PPy structures and 
nanocomposites obtained through the early mentioned, novel, one-step, seeding-template-
assisted, chemical oxidative polymerization reaction of pyrrole provided precious information 
that proves the PPy nanofiber molecules? presence in each nanocomposite. The changing 
characteristics (spectra) of such structures according to the interactions with different metal salt 
solutions were clearly observed. Previously published research study results
20-24
 were also 
consistently matching with the overall results that were obtained through the different FT-IR 
characterizations of these nanocomposite structures. The overall characteristic differences could 
easily be distinguished after a quick revision of so-called graphics, according to the peak 
positions (longer-shorter wave numbers) and their intensities (higer/lower). 
3.2.6 SEM Characterization Results of Microwave Treated Nanocomposites 
As it was explained at the end of the previous chapter, as-prepared nanocomposite 
samples were exposed to microwave irradiation to convert their PPy nanofiber based matrixes in 
carbon nanofibers coated with noble metal nanoparticles. Different characterization results 
collected from so-called samples were given and discussed in details, during the following 
paragraphs. 
Again, first of all, to investigate the morphology of as-prepared structures, carbon 
nanocomposite samples of PPy/AuCl (0.02M), PPy/HAuCl
4
 (0.01M), PPy/PtCl
2
 (0.02M) and 
PPy/PtCl
4
 (0.02M) after 40s, 70s, 6min. and 2min.15s microwave treatment, respectively, were 
selected to take the SEM images. 
 
81 
?
 
Figure 62 SEM image of microwaved PPy/AuCl nanocomposite (scale bar: 1?m) 
 
From those images, five different measurements were taken to have more clear idea about 
the possible morphological changes that had taken place after the treatments. Generally, during 
the tests it was clearly observed that nanocomposites obtained from Au salt solutions exhibited 
higher reactivity to microwave irradiation than the ones obtained from Pt salt solutions. It was 
supposedly a kind of reflectance of the specific noble metal characteristics (reactivity/inertness) 
that were already available in nanocomposite structures.  
 
82 
?
 
Figure 63 SEM image of microwaved PPy/HAuCl
4
 nanocomposite (scale bar: 1?m) 
 
When the SEM images of two different nanocomposites obtained from Au salt solutions 
were investigated; uniformly distributed individual carbon nanofibers could easily be observed 
among the noble metal nanoparticle aggregates. PPy/AuCl CNC was exhibiting individually 
bended morphologies, with uniform diameters around 91nm, that were well dispersed among 
mostly spherical shaped, irregularly aggregated noble metal nanoparticles with several hundred 
nm (~972.6nm) average particle sizes.  
 
83 
?
 
Figure 64 SEM image of microwaved PPy/PtCl
2
 nanocomposite (scale bar: 1?m) 
 
When the SEM image of microwaved PPy/HAuCl
4
 nanocomposite sample was 
investigated, the traditional web-like carbon nanofiber structures that had less smooth surfaces 
with, averagely, 96nm diameters were clearly observed. Mostly spherical shaped noble metal 
particle aggregations with more than 1?m particle sizes (averagely 1076.8nm) became more 
obvious (as a result of burned down and converted PPy nanofiber matrix after being 
microwaved) through the nanocomposite structure.  
 
84 
?
 
Figure 65 SEM image of microwaved PPy/PtCl
4
 nanocomposite (scale bar: 1?m) 
 
SEM images of microwaved nanocomposite structures obtained from different Pt salt 
solutions were exhibiting very similar morphology characteristics with their non-microwaved 
versions. Intricate, web-like carbon nanofibers that were converted from the PPy/PtCl
2
 
nanocomposite matrix surface (by definitely proving the success of previously explained 
mechanism) with the diameter averages of 61nm and decorated with averagely 518.5nm sizes 
irregularly aggregated noble metal nanoparticles, were clearly detected at this samples? SEM 
image.  
85 
?
Carbon nanofibers formed on the PPy/PtCl
4 
nanocomposite after microwave treatment 
were exhibiting individually grown and less smooth morphological properties with a uniform 
diameter distribution around 87nm which were clearly observed from the last SEM image above. 
Spherical noble metal nanoparticle aggregates having several hundred nm particle sizes 
(689.6nm) could also obviously be seen at the final nanocomposite surface after the applied 
microwave irradiation. 
In summary; through a facile,one-step and short term microwave treatment of as-prepared 
PPy nanofiber based composites it was possible to successfully convert the polymer matrix into 
carbon nanofibers that had uniform diameter distributions and similar morphological properties 
like the original PPy nanocomposites.    
3.2.7 TGA Characterization Results of Microwave Treated Nanocomposites 
Thermal characterization was applied to the as-prepared microwaved carbon 
nanocomposite samples and also to the microwaved PPy structures (fiber/granule) with different 
morphologies by using TGA instrument to observe the changes that might have happened after 
the treatment, in terms of thermal stability and the residual material weight of so-called 
structures. Collected TGA graphics were listed and the results generated from those graphics 
were discussed in a comparative manner during the following paragraphs. 
 
86 
?
  
 
 
Figure 66 Comparative TGA graphics of non-/microwaved PPy fiber and PPy granule 
 
TGA results of the different morphology PPy structures were firstly investigated in a 
comparative way with the non-microwaved versions of the same samples. According to the 40s 
microwaved PPy fibers? TGA graphic (represented in black color) only 2.7% of the sample 
weight was lost upon heating from the initial temperature up to 400?C where the material was 
slightly started being decomposed. Initial decomposition temperature range was between 200?C 
to 250?C for the non-microwaved PPy fiber. The major loss of weight from the sample (~70%) 
87 
?
was observed between the temperatures of 400?C to 770?C (averagely between 480?C to 630?C). 
After 750?C the weight of the sample became constant and the final readings were showing that 
~27% of the sample weight was remained, which was supposedly the weight of CNCs produced 
in the material structure during the microwave treatment. 
    
  
Figure 67 Comparative TGA graphics of non-/microwaved PPy/AuCl with microwaved PPy 
fiber and PPy granule 
 
Comparatively, non-/microwaved PPy granules? TGA results (represented in dashed red 
color) were showing better results than PPy fibers. Only ~1.5% of the initial weight was lost as a 
result of heating from the starting temperature to 450?C where the sample was started being 
decomposed. 67.3% of the sample was majorly decomposed between the temperatures of 450?C 
to 750?C (averagely 564?C to 586?C). Finally, after 750?C the sample weight became constant 
and there was ~31% of the residual sample, which was possibly again the amount of carbon 
structures converted in the structure, left in the TGA pan.       
 
88 
?
  
Figure 68 Comparative TGA graphics of non-/microwaved PPy/HAuCl
4
 with microwaved PPy 
fiber and PPy granule 
 
After the thermal analysis of microwaved PPy fiber and granules, 40s microwaved and 
non-microwaved PPy/AuCl (0.02M) nanocomposite samples? TGA results were investigated.  
According to the graphics (represented with green color), significant improvements were 
observed in the thermal stability and the residual amount of samples (due to the converted carbon 
nanofibers in the structure) after microwave treatment. 1.7% of the sample weight was lost upon 
heating from the initial temperature up to 350?C, where the major decomposition of the sample 
was started. From 350?C to 750?C, (averagely between 411?C to 571?C) 26% of the sample was 
decomposed. Finally, 72.3% (previously 70% for the non-microwaved nanocomposite) of the 
total sample weight was remained, which was believed to be weight of newly generated CNCs 
and the noble metal nanoparticles in its structure.  
 
89 
?
  
Figure 69 Comparative TGA graphics of non-/microwaved PPy/PtCl
4
 with microwaved PPy 
fiber and PPy granule 
 
The thermal analysis of the 70s microwaved PPy/HAuCl
4
 (0.01M) nanocomposite was 
also exhibiting superior results in terms of thermal stability and the residual sample weight, than 
its non-microwaved version. 2.4% of the sample weight was lost during the initial heating of 
microwaved nanocomposite sample, starting from the initial temperature to 250?C. The major 
decomposition of the sample (~29.7%) took place between the temperatures of 250?C to 750?C 
(averagely between 346?C to 508?C). Finally, 67.8% of the nanocomposite weight, which could 
be considered as the weight of as-prepared CNCs and the noble metal nanoparticles in the 
structure, was remained (previously 65% for the non-microwaved version) in the TGA pan. 
Nanocomposites from PPy/PtCl
2
 (0.02M) was microwaved for 6min. under standard 
conditions but there was no clear burning (sparkles and/or little flames), indicating the 
conversion of PPy nanofibers to CNCs at the surface, observed during the treatment. TGA 
analysis of that sample was not presented here due to this extraordinary situation. 
90 
?
Final thermal characterization result was belong to the 2min.15s microwaved (microwave 
treatment times were varying due to the relative reactivity of different noble metals) PPy/PtCl
4
 
nanocomposite sample which exhibited the best improvements in terms of thermal stability and 
the residual amount of weight after thermal heating (indicating the high rate of generation of 
CNCs in its nanocomposite structure). Only 2% of the sample weight was decomposed upon the 
initial heating from the starting temperature to 250?C. Likewise the other nanocomposites, the 
major decomposition (~37.5%) of this sample also took place between the temperatures from 
250?C to 750?C (mainly between 300?C to 537?C). At the end of the thermal application, 60.6% 
of the sample weight was remained in the TGA pan, (previously 48% for the non-microwaved 
version), which considered to be mainly composed of noble metal nanoparticles and as-prepared 
CNCs in the nanocomposite structure. 
In short, this newly developed, simple and one-step microwave treatment method to 
convert nanocomposite structures to carbon nanocomposites in seconds was obviously 
successful. CNC conversion rates and the improved thermal properties of so-called 
nanocomposites were also strongly supporting the success of this rapid and facile mechanism for 
bulk CNC synthesis. 
3.2.8 EDX Analysis Results of Microwave Treated Nanocomposites 
EDX elemental analysis was the next characterization applied to the microwave treated 
nanocomposites. Weight % values of C, N, O, Cl, V, Au and Pt elements within these so-called 
microwaved structures were summarized in the following table. 
 
 
 
91 
?
Table 7 Summary of the EDX analysis results of the microwaved nanocomposite structures 
Sample C N O Cl V Au / Pt Total 
PPy/AuCl 
0.02M 
10.71 4.86 -0.82 0.26 0.11 84.87 100 
PPy/HAuCl
4
 
0.01M 
29.97 3.42 0.62 0.24 0.10 65.66 100 
PPy/PtCl
2
 
0.02M 
24.78 5.50 5.55 11.59 0.28 52.30 100 
PPy/PtCl
4
 
0.02M 
31.19 1.09 1.29 0.14 0.14 66.14 100 
 
Based on the EDX analysis results above, calculations were made to find out the exact 
chemical formulas of microwaved nanocomposite structures by following the previously 
described method.  
Here, again N% values of each sample was considered as the representative for the PPy 
part of the chemical formulas rather than C% to avoid the possible distractions originated from 
the supporting carbon tape used. The failure at the microwave treatment of PPy/PtCl
2
 (0.02M) 
nanocomposite was negatively effected the EDX analysis results, with the excessive amount of O 
detected in its structure which was considered as the representative for the H
2
O part of the 
chemical formula and supposed to be very close to/or zero after being microwaved, was proving 
this failure.  
In view of the results listed above and the calculations made based on them, the chemical 
formulations of microwave treated nanocomposite samples were listed as; (PPy)(Cl)
0.021
(Au)
1.241
, 
(PPy)(Cl)
0.027
(Au)
1.366
, (PPy)(Cl)
0.833
(Pt)
0.684
, (PPy)(Cl)
0.05
(Pt)
4.358
, respectively, for the 
nanocomposites presented in the table.  
92 
?
As a result, the EDX analysis data were also consistently supporting the success of this 
facile, rapid and one-step microwave treatment technique to convert as-prepared nanocomposites 
into CNCs. Higher C:N ratios ranging between 5-28 (which were previously around 4-6 for non-
microwaved nanocomposites), the absence of H
2
O molecules in chemical structure and higer 
proportions of noble metals (currently ranging between 0.684 to 4.358 and was previously 0.318 
to 0.697) in the final nanocomposite structures, were the other important observations made 
which were also proving the success of this method. 
3.2.9 FT-IR Characterization Results of Microwave Treated Nanocomposites 
After the elemental analysis of as-prepared CNCs by microwave treatments, sequential 
FT-IR characterizations were also conducted with the same samples and also with the 
microwaved, different morphology PPy structures to verify the success of this approach. 
  
  
Figure 70 FT-IR spectra of microwaved PPy fiber and microwaved PPy granule 
 
According to the FT-IR graphics listed below, there were not many characteristic peaks 
detected which could indicate the specific functional groups in those structures, except the ones 
93 
?
recorded from PPy fiber at corresponding wave number of 771.7cm
-1
 (indicating N-H 
vibrations), from PPy granule at corresponding wavenumbers of 750.1cm
-1
 and 630.4cm
-1
 (both 
indicating N-H stretchings) and from PPy/HAuCl
4
 (0.01M) nanocomposite sample at 
corresponding wavenumber of 1402cm
-1
 (again indicating the N-H bond in the structure). 
 
  
Figure 71 FT-IR spectra of microwaved PPy/AuCl and microwaved PPy/HAuCl
4
 
nanocomposites 
 
 
Figure 72 FT-IR spectra of microwaved PPy/PtCl
2
 and microwaved PPy/PtCl
4
 nanocomposites 
94 
?
In summary, FT-IR characterization of microwaved nanocomposites were once again 
proved the success of this facile and one-step technique for CNC production from different 
nanocomposite structures after very short term microwave treatments, by verfying the high 
conversion of PPy nanofiber matrix -whose characteristic peaks were hardly been detected in 
such graphics after the treatments- to CNCs. Seldom characteristic peak values that have been 
detected in above mentioned microwaved samples? FT-IR graphics were compatible with the 
previous study results
25-27
 found in the literature.  
Consistently with the proved success of this simple, rapid and one-step microwave 
treatment method and its elaborately explained mechanism it was possible to generate bulk 
quantities of CNCs with uniformly retained morphological properties directly from conducting 
polymer nanocomposites
18
.  
This unique method could open new windows in design and development of new-
generation fuel-cell membranes (by maintaining the electrochemical properties of conducting 
polymer/noble metal nanocomposites), energy storage systems and high sensitivity volatile 
organic molecule sensors based on CNCs
18
. 
3.2.10 Four Probe Conductivity Measurement Results of Different Polymeric and 
Nanocomposite Structures 
One of the major characterizations of as-prepared different morphology PPy structures 
(fiber/granule) and  four different conducting polymer nanocomposites obtained from standard 
noble metal salt solutions (0.02M) were conducted by using previously described linear four 
probe conductivity measurement method to gain a deeper knowledge about the electrical 
properties of so-called structures. Six different samples were prepared by applying high pressure 
(3500psi) onto them while they were filling a mold cavity with certain dimensions (LxWxH = 
95 
?
1.5cm x 0.2cm x 0.225cm). Specific thickness (heigth) values of each thin film was measured to 
determine the crossectional area (A) that was necessary to calculate the conductivity of each 
sample. Since the conductivity (S/cm) is the reciprocal of resistivity (R) and can be calculated 
with the equation of [? = L/(R x A)]
19
 it was easy to obtain the required data by simply touching 
the four probes onto the thin film surfaces to read the specific resistance values from the 
connected device.  Here, L represents the distance (0.52cm) between the two inner probes. A 
simple representation of the utilizd linear four probe method was shown in the figure below. 
 
 
Figure 73 Linear four probes and a representative sample bar
19
 
 
 
 
 
 
 
96 
?
Table 8 Summary of the calculated values of samples used for conductivity measurements 
Sample  Thickness (cm)  Resistance (?) Conductivity (S/cm)
PPy fiber 0.055 26 1.82 
PPy granule 0.08 18.9 1.72 
PPy/AuCl 0.055 2420 0.0195 
PPy/HAuCl
4
 0.09 1260 0.023 
PPy/PtCl
2
 0.07 2600 0.0143 
PPy/PtCl
4
 1 2400 0.0011 
 
In summary, previously described linear four probe conductivity measurement method 
was successfully utilized to define the specific conductivity values of as-prepared polymeric and 
nanocomposite structures.  
According to the results, PPy fibers exhibited a higher conductivity value than the 
granule sample, probably because of its higher surface area and more regularly aligned 
morphology which made easier for electrons to move through. Compared to the conventionally 
prepared PPy structures (PPy.Cl obtained from HCl)
19
, these samples were exhibiting less 
conductivity due to their less doping level, provided by Cl
- 
ions, of their structures and the type 
of the reaction media used (HCl>H
2
O) for their preparation. Generally, different morphology 
PPy structures were exhibiting higer conductivity values than the nanocomposite samples. There 
were three possible main reasons listed as; (i) very low doping levels, provided by Cl
-
 ions, of 
their structures (because of using 0.02M, 0.01M and 0.005M concentrated solutions, compared 
to 1M HCl used in conventional PPy synthesis, of noble metal salts Cl
-
 amount provided was 
very less), (ii) the large interfaces (junctions) between the noble metal nanoparticle aggregates 
97 
?
and the PPy nanofiber matrix which were supposed to increase the conductivity but contrastingly 
decreasing it by being large obstacles against the electrons moving through their structure, (iii) 
using aqueous system, which has less ionic potential, rather than HCl as the reaction media, 
causing the above mentioned situation.  
3.2.11 Cyclic Voltammetry (CV) Application Results of Different Polymeric and 
Nanocomposite Structures     
Four different polymeric and nanocomposite structures (PPy fiber, PPy/PtCl
2
 (0.02M), 
PPy/PtCl
2
 (0.01M), PPy/PtCl
2
 (0.005M) and microwaved PPy/PtCl
2
 (0.01M)) were utilized to 
conduct electrochemical cyclic voltammetry (CV) applications by using Arbin-010 MITS Pro 4-
BT 2000 instrument at standard laboratory conditions upon applying a sweeping potential within 
-0.8V to 0.4V at 20mV/s range vs. SCE used as the reference electrode. A modified pure 
graphite rod was used as the counter electrode and similar graphite rods with above mentioned 
polymeric structures pasted at their tips by colloidal carbon, were used as the working electrodes. 
76mL of 1M KOH aqueous solution mixed with 4mL methanol -CH
3
OH- (5% of total volume of 
80mL) was used as the electrolyte for these applications.  
The purpose of this application was to obtain certain information about the 
electrochemical behavior of different as-prepared polymeric nano/structures and to verify their 
applicability in fuel-cells via detecting the oxidation of methanol in their test results. Cyclic 
voltammograms (CVs) of each sample and related discussions were listed along the following 
paragraphs. 
98 
?
   
Figure 74 CVs of pure graphite rod and PPy fiber coated graphite rod 
 
The lowest current range readings (-0.05mA to 0.05mA) were obtained from the CV of 
pure graphite rod as the control sample, whose results was represented in black color, as 
expected.  
Due to the inertness of its pure carbon structure against CH
3
OH it was not easy detect any 
significant peaks referring the oxidation of CH
3
OH. Characteristic oxidation peaks that were 
supposedly belong to the CH
3
OH (during charging around -0.1V) and CO (the by product of 
slightly oxidized methanol according to the reactions of (CH
3
OH + Pt              Pt-CO + 4Pt-H 
and 4Pt-H              4Pt + 4H
+
 + 4e
- 
and Pt-CO + H
2
O             CO
2
 + 2H
+
 + 2e
-
) during discharge 
around -0.3V could barely be seen from the CV of the pure graphite rod verfying a very weak 
oxidation reaction that might have happened. 
The CV of PPy fiber coated graphite rod, which was represented in red color, was 
exhibiting the largest current range readings (-6mA to 10mA) without any peak indicating the 
oxidation of CH
3
OH due to the lack of elements that could catalyze the so-called reaction, in its 
polymeric structure. 
99 
?
  
Figure 75 CVs of PPy/PtCl
2
 (0.02M) and PPy/PtCl
2
 (0.01M) nanocomposite coated graphite rods 
 
CVs of PPy/PtCl
2
 nanocomposites (represented in green and blue colors) obtained from 
different concentrated solutions were clearly proving the accrued oxidation reactions of CH
3
OH 
upon the applied potential during the tests. The largest current range readings (from -5mA to 
10mA) were obtained from the CV of PPy/PtCl
2 
(0.02M) nanocomposite coated graphite rod, 
represented in green color. A sharp oxidation peak of CH
3
OH around -0.1V, and another very 
broad oxidation peak, located between -0.3V and -0.2V (indicating the oxidation of CO) during 
discharge could be observed from the voltammogram. The CV of PPy/PtCl
2 
(0.01M) 
nanocomposite coated graphite rod had a narrower current range between -0.75mA to 1.75mA 
supposedly indicating a milder oxidation reaction of CH
3
OH. A broad oxidation peak of CH
3
OH 
located between -0.1V and 0V and another very weak oxidation peak of CO placed between -
0.4V to -0.3V were both proving the success of the electrochemical oxidation of CH
3
OH 
catalyzed by noble Pt elements in such nanocomposite structures. 
 
100 
?
  
Figure 76 CVs of PPy/PtCl
2
 (0.005M) and microwaved PPy/PtCl
2
 (0.01M) nanocomposite 
coated graphite rods 
 
The last two voltammograms, represented in cyan and magenta colors, were belong to the 
PPy/PtCl
2
 (0.005M) and microwaved PPy/PtCl
2
 (0.001M) nanocomposites coated graphite rods, 
respectively.  
The one belong to the PPy/PtCl
2
 (0.005M) nanocomposite coated graphite rod was 
exhibiting the second largest current range (between -3mA to 3.5mA) among all nanocomposite 
structures. There were again two oxidation peaks clearly be seen at this voltammogram. A wide 
and sharp CH
3
OH oxidation peak located around -0.2V and another weaker one indicating the 
CO oxidation located around -0.4V were still in good agreement with the already taken place 
oxidation reaction of CH
3
OH. Lastly, the CV of microwaved PPy/PtCl
2 
nanocomposite obtained 
from 0.01M salt solution was investigated. The results were also indicating a similar current 
capacity (-1mA to 1.5mA) for this nanocomposite likely to its non-microwaved verison. A very 
broad CH
3
OH oxidation peak located around -0.2V and another very weak and broad one, 
101 
?
located around -0.4V at this sample?s CV once again proved the success of the electrochemical 
application even after the microwave treatment.  
In summary, the overall CV applications of non-/microwaved PPy/PtCl
2 
nanocomposites 
from different concentrated noble metal salt solutions were consistently able to catalyze the 
oxidation of methanol through a series of electrochemical reactions.  
Here, concentrations of the noble metal salt solutions, which directly determine the metal 
amount incorporated in the nanocomposite structure, were playing a vital role for the fate of so-
called reactions. The direct relationship between the amount of noble metals in the structure and 
the current capacity of the oxidation reactions could also be observed from the comparative CVs 
of different samples above. As a result, our novel, one-step, seeding-template-assisted chemical 
oxidative polymerization of pyrrole, conducted in different concentrated aqueous solutions of 
various noble metal salts, was able to produce nanocomposite structures that were composed of 
PPy nanofibers decorated with noble metal nanoparticles which could catalyze the oxidation 
reaction of CH
3
OH witin its traditional fuel-cell solution with KOH via applying sweeping 
potential.  
Increased surface area of so-called, non-/microwaved, nanocomposites helped both to 
improve the electrochemical properties and also the distributions of noble metal nanoparticles in 
a fuel-cell membrane. It was believed that this kind of nanocomposite structures would play an 
important role in the development of highly efficient, next-generation fuel-cell devices
12, 15
.   
 
 
 
 
102 
?
 
 
 
CHAPTER 4 
CONCLUSIONS AND THE FUTURE WORK 
 
 4.1 Conclusions 
To control, investigate, improve and characterize the several properties of conducting 
polymer based different nanocomposites and to find out the effects of the noble metal salt 
solution concentrations besides the other reaction and application parameters (the use of V
2
O
5
 
sol-gel nanofibers, microwave treatment?etc.) on the final nanocomposite morphologies and 
properties, this project was undertaken in details throughout this Master?s thesis. 
In this study; (i) a novel, one-step, seeding-template-assisted chemical oxidative 
polymerization of pyrrole monomers in different concentrated four types of aqueous Au and Pt 
salt solutions to produce PPy nanofiber (with 25-70nm diameters) based nanocomposites 
decorated with well dispersed noble metal nanoparticles, (ii) another facile, one-step and rapid 
microwave treatment approach with different as-prepared nanocomposites to convert their 
structures into CNCs by retaining their morphologies, (iii) effectively use of noble metal salts as 
the dopant and the oxidative agent for pyrrole monomers in stead of large, toxic oxidants (like 
APS) to initiate their polymerization reaction, and (v) according to a previously mentioned 
approach
11
, i.e., the use of degradable, oxidative-reactive V
2
O
5
 sol-gel nanofibers as the seeding 
templates to initiate and maintain bulk nanofibrillar morphology during the polymerization 
reaction of pyrrole, were ?for the first time? described in details.  
103 
?
Also, with the intrinsic catalysis property provided by noble metal particles in their 
structure of so-called non-/microwaved nanocomposites were proven to be promising 
infrastructure materials for the design and development of new-generation fuel-cell membranes 
in the future. 
4.2 Future Work 
All those unique knowledge, gained from the overall experimental and applied studies, 
would be canalized to perform similar research activities by utilizing other intrinsic conducting 
polymers like PANI and/or PEDOT with different noble metal salts like silver nitrate (AgNO
3
) 
and copper chloride (CuCl
2
) to produce well-defined nanocomposites with superior properties, 
which will also be promising candidates for the different industrial applications, in the future.        
                   
 
 
 
 
   
 
   
 
 
 
 
 
104 
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