A new soluble conducting polymer and its electrochromic devices

A new polythiophene derivative was synthesized by both chemical and electrochemical oxidative polymerization of 1-(1-phenylethyl)-2,5-di(2-thienyl)-1H-pyrrole (PETPy). Of which the chemical method produces a polymer that is completely soluble in organic solvents. The structures of both the monomer and the soluble polymer were elucidated by nuclear magnetic resonance (H-1 and C-13 NMR) and Fourier transform infrared (FTIR) spectroscopy. The average molecular weight has been determined by gel permeation chromatography to be M-n = 3.29 x 10(3) for the chemically synthesized polymer. Polymer of PETPy was synthesized via potentiostatic electrochemical polymerization in acetonitrile (AN)/NaClO4/LiClO4 (0.1 M) solvent-electrolyte couple. Characterizations of the resulting polymer were performed by cyclic voltammetry, FTIR, scanning electron microscopy, and UV-vis spectroscopy. Four-probe technique was used to measure the conductivities of the samples. Moreover, the spectroelectrochemical and electrochromic properties of the polymer films were investigated. In addition, dual-type polymer electrochromic devices based on P(PETP,) with poly(3,4-ethylenedioxythiophene) were constructed. Spectroelectrochemistry, electrochromic switching, and open circuit stability of the devices were studied. They were found to have good switching times, reasonable contrasts, and optical memories. (c) 2006 Wiley Periodicals, Inc