Improving the electrical conductivity of polymer acid-doped polyaniline by controlling the template molecular weight

Abstract

We report the synthesis and characterization of a series of polyanilines (PANI) that are templated with a polymer acid at varying molecular weights. The polymer acid template of choice, poly(2-acrylamido-2-methyl-1-propanesulfonic acid), or PAAMPSA, was synthesized via conventional free-radical polymerization with molecular weights ranging from 45 kg mol⁻¹ to 724 kg mol⁻¹. Subsequent aniline polymerization in the presence of PAAMPSA yielded water-dispersible, conductive PANI–PAAMPSA. The electrical conductivity of PANI–PAAMPSA increases by approximately three-fold with decreasing PAAMPSA molecular weight. This trend is accompanied by significant structural changes, including increases in PANI crystallinity and conjugation length. These conductivities (0.4–1.1 S cm⁻¹) exceed the highest reported for polymer acid-doped PANI systems.