Effects of crosslinking on polyaniline films' doping behavior and degradation under weathering

Abstract

The effects of crosslinking on solution cast polyaniline films were investigated by means of X-ray photoelectron spectroscopy, atomic force microscopy, bulk elemental analysis, resistivity and tensile strength measurements. By comparing the anion/N molar ratio at the surface and bulk of the film, it was found that crosslinking of the films retards the dopant infusion process during reprotonation. The extent of doping has a significant effect not only on the film's resistivity, but also its tensile strength. Under simulated weathering, the degradation mechanisms of the non- crosslinked and crosslinked films are similar. As a result of the reactions occurring in the polyaniline chains under simulated weathering, profound changes in the chemical state of the C and N species are evident. In addition to the changes in the film's physical and electrical characteristics, the surface morphology of the films also undergoes substantial changes, especially for the reprotonated crosslinked films.