Synthesis and characterization of polyaniline nanoparticles in SDS micellar solutions

Polyaniline (PANI) dispersions consisting of 10-20 nm sized nanoparticles w ere prepared by oxidation with ammonium peroxydisulfate (APS) in sodium dod ecylsulfate (SDS) micellar solutions. Coalescence and coagulation were prev ented by electrostatic repulsive interaction between anionic SDS micelles. Particle morphology was dependent on the initial shape of surfactant aggreg ates (micelles) and the molar ratio of SDS to aniline monomer. Spherical pa rticles were obtained at very low monomer concentration and the shape of pa rticles began to be distorted from the spherical shape as monomer concentra tion increased at constant 0.2 M SDS concentration. The size of spherical p articles was the same order of the micellar size or slightly larger. UV-VIS spectroscopy, compositions of PANI powder, morphology, crystalline structu re, thermal stability, molecular weight and conductivity of PANI particles synthesized at various monomer and surfactant concentrations were investiga ted. (C) 2001 Elsevier Science B.V. All rights reserved.