New Evidence Supporting the Interfacial Model of Electrically Conductive Polymer Composites. 3. Morphological Study of Polyaniline-Poly(ethylene-co-vinyl acetate) Composites

Abstract

A detailed study of the morphological features of polyaniline-poly(ethylene-co-vinyl acetate) (PANI-EVA) composites is presented. It is shown that their microstructure consists of highly ordered electrically conductive PANI paths embedded in the insulating EVA matrix. Long fibrils of PANI and interconnected fractal-like networks were also observed. It was found that the size of the primary PANI particles was ca. 5–10 nm. A spontaneous flocculation of these particles contributed to the formation of conductive pathways at extremely low percolation thresholds (Φc) (loading level ca. 0.005 wt. fraction). The sizes of the PANI domains varied during storage of the films and a key property of the conductive constituent (the PANI phase) was observed, namely a tendency for its solid state rearrangement. This PANI self-organization has been interpreted according to the new interfacial model of polymer composites.