Morphology of conductive, solution-processed blends of polyaniline and poly(methyl methacrylate)

Abstract

The morphology of solution-processed polyblends of poly(methyl methacrylate) (PMMA) and the electrically conductive polyaniline-camphor sulfonic acid complex (PANI-CSA) was investigated using transmission electron microscopy. This study unveiled a remarkable, interpenetrating network of fibrillar, crystalline PANI within the PMMA matrix, consistent with the existence of connected conducting paths at volume fractions as low as 1 wt.% of the conductive polymer. In this dilute regime, the PANI morphology is a tenuous, interconnected fibrillar network with characteristic cross-sectional fibril dimensions of a few tens of nanometers. At higher fractions of PANI, the density of connected paths increases and the morphology appears foam-like with the PANI network surrounding the PMMA phase. This unusual morphology is the origin of the high electrical conductivities and the excellent optical quality of the PANI-CSA-PMMA blends.