Synthesis and properties of silica/polystyrene/polyaniline conductive composite particles

In this study, silica/polystyrene/polyaniline (SiO 2 /PS/PANI) conductive composite particles were synthesized by four sequential reactions. The nanosized SiO 2 particles were synthesized from tetraethoxysilane (TEOS) by a sol–gel process with water as the solvent medium, followed by a surface modification with triethoxyvinylsilane; then the surface modified SiO 2 particles were used as seeds to synthesize SiO 2 /PS composite particles with soapless seeded emulsion polymerization. Finally, the SiO 2 /PS particles were used as seeds to synthesize the SiO 2 /PS/PANI conductive composite particles. The sol–gel process of SiO 2 , the effect of surface modification, and several other factors that influenced polymerization of styrene in the soapless seeded emulsion polymerization will be discussed. Either potassium persulfate (KPS) or 2,2′‐azobis(isobutyramidine) dihydrochloride (AIBA) was used as the initiator to synthesize the uniform SiO 2 /PS particles successfully, and the cross‐section morphology of the SiO 2 /PS particles was found to be of a core–shell structure, with SiO 2 as the core, and PS as the shell. The SiO 2 /PS particles were well dispersed in many organic solvents. In the following step to synthesize SiO 2 /PS/PANI conductive composite particles, sodium dodecyl sulfate (SDS) played an important role, specifically, to absorb aniline onto the surfaces of the SiO 2 /PS particles to carry out the polymerization of aniline over the entire surface of the particles. The conductivity of the SiO 2 /PS/PANI composite particles approached that of semiconductive materials.