Poly(aniline- co-pyrrole): powders, films, and colloids. Thermophoretic mobility of colloidal particles

Abstract

Copolymers of aniline and pyrrole have been prepared by the oxidation of monomer mixtures of various compositions with ammonium peroxydisulfate. The copolymers have a lower conductivity than the corresponding parent homopolymers or are even non-conducting. This means that sequences of constitutional units, responsible for the conduction, are disrupted by the incorporation of the second comonomer. The ability of both comonomers to copolymerise has been proved on the basis of FTIR spectra. Thin copolymer films grow during copolymerization on glass supports immersed in the reaction mixture. Their thickness of ∼130 nm, estimated by optical absorption, is little dependent on the monomer mixture composition. Colloidal copolymer dispersions are produced when the polymerization is carried out in the presence of a steric stabilizer, poly( N-vinylpyrrolidone). The particle size 200–500 nm, determined by dynamic light scattering (DLS), does not significantly depend on the content of aniline in the reaction mixture. The thermophoretic mobility observed in micro-thermal field-flow fractionation (micro-TFFF) experiments abruptly changes with the composition of copolymer colloidal particles. Recent lack of information on the thermal conductivity of the studied copolymers does not allow one to interpret quantitatively the results of micro-TFFF, however, it is interesting to note a strong coherence of the amplitude of thermal diffusion coefficients and the electrical conductivity of the studied copolymer colloidal particles.