Mechanism of formation of polyaniline flakes with high degree of crystallization using a soft template in the presence of cetyltrimethy-lammonium bromide

Abstract

Flake-like polyaniline with various thicknesses was prepared by cationic emulsion polymerization of aniline monomer in the presence of cetyltrimethylammonium bromide (CTAB). The morphology of polyaniline with uniform and smooth flake-like structure was observed using field-emission scanning electron microscopy and transmission electron microscopy. The lamellar complex of (CTA)2S2O8, acting as a reactive soft template for the formation of polyaniline, was investigated using low-angle X-ray diffraction. The soft template provides an expanding space for the growth of polyaniline, in which the oxidization of aniline monomers can construct effectively a flake-like structure. The concentration of CTAB plays an important role in adjusting the d-spacing of the soft template. Crystallization and composition of polyaniline were characterized using X-ray diffraction and Fourier transform infrared spectroscopy. The X-ray diffraction pattern has a sharp peak at 2θ = 6.4° (d-spacing = 13.7 Å), showing that polyaniline has a solid-state ordering structure and high degree of crystallization. Doping and dispersive experiments were also included in the study. Copyright © 2012 Society of Chemical Industry