Organic Molecule Functionalized Nanoparticles and Redox Active Polymer: Synthesis, Characterization and Application
Type of DegreePhD Dissertation
Chemistry and Biochemistry
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In the field of material chemistry, polymers and nanoparticles are most popular areas of current research and development. These two fields are quickly expanding and playing a vital role in a wide spectrum of areas ranging from electronics to photonics, conducting materials to sensors and medicine to biotechnology during the past decades. This dissertation mainly focuses on the synthesis and characterization of organic-inorganic hybrid nanostructure and redox active polymers. At the beginning of this dissertation, we have reviewed the recent literatures of functionalized nanoparticles and electroactive polymers. In Chapter Two, we report synthesis and characterization of redox active naphthalene diimide (NDI) functionalized metal nanoparticles. Silver and gold nanoparticles were synthesized from silver neodecanoate and gold(I) sodium thiosulfate, respectively, in presence of DPA-NDI-SH (where DPA= Diphenylamine) in a single reaction vessel. Dimethyl sulfoxide (DMSO) and dimethy formamide (DMF) were used as solvents for Ag and Au nanoparticles respectively. The synthesized nanoparticles were characterized by UV-Visible spectroscopy, TEM and X-ray diffraction. Incorporation of DPA-NDI-SH ligands on the surfaces of nanoparticles was confirmed by FT-IR. In Chapter Three, synthesis of a new monomer containing coronene diimide with diphenylamine end group (DCTD) has been demonstrated. Polymer thin films of DCTD were grown onto gold, glassy carbon and ITO electrode surfaces via electropolymerization. Cyclic voltammetry of the resulting polymers show a reversible 2e- oxidation of the diphenylbenzidine unit and reversible reductions of the aromatic diimide. The spectroelectrochemical and electrochromic properties of these films were evaluated. Reversible switching between different colors corresponded to the redox states of diphenylbenzidine and imides were observed. The polymer film morphology was characterized by AFM. Chapter Four discusses the electrochemical and solid state study of bilayer rectifying device. Polymers, poly(FD) and poly(DCTD) were sequentially electrodeposited on Au electrodes and their electrochemical study showed that electrons flow in only one direction in solution with supporting electrolyte. Also p-n junctions with these semiconductor polymers were fabricated and characterized by current-voltage responses and Shockley diode characteristics. We found that the device direction was switched upon changing the assembly order of bilayer. In the final part of this work, we demonstrated that the naphthalene diimide functionalized semiconductor CdS nanoparticles can be synthesized and characterized. CdS nanoparticles were synthesized in DMSO from cadmium acetate and sodium sulfide in presence of naphthalene diimide (DPA-NDI-SH). The synthesized particles were characterized by UV-visible, fluorescence, XRD, TEM and FT-IR.