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Inter-polymer complexes of conducting polymers: Synthesis, characterization and applications

Posted on:2006-05-23Degree:Ph.DType:Dissertation
University:University of Rhode IslandCandidate:Tang, ZhexiongFull Text:PDF
GTID:1451390008457431Subject:Chemistry
Abstract/Summary:
Inter-polymer complexes of conducting polymers between polyelectrolytes and conducting polymers are synthesized by template guided polymerization. In these polymer complexes, polyelectrolytes act as both dopants and steric stabilizers. There are a lot of factors such as molecular weight of template polymer, concentration of adduct solution and mole ratio of template polymer to conducting polymer which influence the dispersibility and morphology of inter-polymer complex. One of the most significant factors is the molecular weight of template polymer. High molecular weight template polymer leads to globular morphology of the complex. These kinds of complexes are dispersible in water. Low molecular weight template polymer leads to fiber morphology of the complex. It forms a precipitate in water. Whether inter-polymer complexes are dispersible or precipitate depends on their morphology in solution. Globular morphology favors dispersible product formation while fiber morphology leads to precipitation. We also synthesized new inorganic/organic nanocomposites with a core/shell structure. The core component is an inorganic oxide (e.g. TiO2 or CeO2), and the shell component is a inter-polymer complex of polyaniline. The electrochemical properties of Poly(acrylic acid):Polyaniline/CeO 2 nanocomposite show electronic interaction between the organic conducting polymer shell and its inorganic core. The inter-polymer complex of polyaniline in the composite shows better pH stability of the conductive form than that of the corresponding single-strand polyaniline in a similar core/shell composite. Finally, thin films of alternating layer composition are constructed from the inter-polymer complexes PEDOT:PSS and the polycation PEI, PAH and PDDA, using ionic self assembly (ISA). These multilayer systems display a consistent trend in film growth, as evidenced by UV-visible spectroscopy and ellipsometry. In detailed electrochemical and spectral investigations, the performance of PEI/PSS:PEDOT as a material for electrochromic applications is extremely competitive. By changing the deposition parameters and the relative film thickness, we obtain the largest optical contrast and maximum absorption of the neutral, reduced form for the film at 643 nm, with a change in transmittance of 51%.
Keywords/Search Tags:Polymer, Template, Molecular weight
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