Abstract
The present study is aimed to elucidate main structural features of polymeric sulfonic acids (the rigidity of main chain, the distance between sulfonic groups on the chain, the hydrophobicity of main chain or side fragments) on the course of 3,4-ethylenedioxythiophene (EDOT) electropolymerization and electronic and chemical structure of the poly(3,4-ethylenedioxythiophene) (PEDOT) films obtained. The films were prepared by electrochemical polymerization in cyclic voltammetry, potentiostatic, and galvanostatic regimes in aqueous solutions of different polyacids in the absence of supporting electrolyte. The effect of the chemical structure of polyacid on the course and rate of PEDOT synthesis was traced by electrochemical and in situ UV-Vis spectroscopic methods. It was shown that the highest rate of EDOT electropolymerization is achieved in the presence of flexible-chain polyacid having hydrophobic fragments (groups) in its structure, followed by hydrophobic rigid-chain polyacids. The lowest rate was observed in the presence of hydrophilic flexible-chain polyacid. The electronic and chemical structure of the PEDOT films obtained was studied by in situ UV-Vis-NIR and Raman spectroelectrochemistry. The films prepared in the presence of rigid-chain polyacids at high anodic potentials demonstrate decreased content of bipolaronic fragments in their structure, while PEDOT complexes with flexible-chain polyacids are very much like conventional polymer prepared in non-aqueous medium. The results are discussed in terms of conformational state (ability to form coils and thus concentrate the monomer) of different polyacids in aqueous solution and hydrophobic interactions between the polyacids and EDOT.
Published Version
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