Thermal stability investigation of pedot films from chemical oxidation and prepolymerized dispersion

Abstract

Poly(3,4-ethylenedioxythiophene) (PEDOT) films were produced by chemical oxidative polymerization (in-situ PEDOT) and coating aqueous dispersion (slurry PEDOT). Sheet resistance measured before and after heat treatment showed that slurry PEDOT film remained stable in air while in-situ film degraded resulting in a significant increase in resistance. Excellent stability of slurry film was credited to its PEDOT-rich core, Poly(styrenesulfonic acid) (PSS)-rich shell structure, and high molecular weight (Mw) PSS dopant while the degradation of in-situ PEDOT was attributed to oxidation by oxygen in air. Thermal analysis data supported this hypothesis. Fourier Transform Infrared (FT-IR) spectrometry and X-ray photoelectron spectroscopy (XPS) results indicated that C=C bond breaking and decreased doping level were responsible for poor stability of in-situ film in air. © The Electrochemical Society of Japan, All rights reserved.