Preparation of PANI-coated poly(styrene-co-styrene sulfonate) nanoparticles

Poly(styrene-co-styrene sulfonate) (PS-PSS) latexes have been coated with thin overlayer of polyaniline (PANI) to produce electrically conductive 'core-shell' particles (PANI/PS-PSS) in the size of range 30-50 nm in diameter. PS-PSS core particles were prepared by radical emulsion copolymerization and PANI was oxidatively polymerized using ammonium peroxydisulfate (APS) on the surface of PS-PSS latex. PANI thin overlayer was observed in transmission electron microscopy (TEM) images indicating polymerization of aniline takes place preferably on the PS-PSS surface rather than in the aqueous bulk phase. Elemental analysis revealed that the weight percent of styrene sulfonate in PS-PSS copolymer was ca. 5.4% and the conductivities of PANT PS-PSS pellets were greatly increased with the increase of nitrogen content. Thermal gravimetric analysis (TGA) thermograms showed two main degradation stages beginning at 360 and 460 degreesC that correspond to the decomposition of PS-PSS and PANI, respectively. (C) 2001 Elsevier Science Ltd. All rights reserved.