Bottom-up synthesis of PS-CNF nanocomposites

Polystyrene-carbon nanofiber (CNF) nanocomposites have been synthesized by a ‘bottom-up’ method through electrostatic assembly. First, a cationic polystyrene (PS) latex was synthesized by conventional emulsion polymerization. The latex was mixed with an aqueous suspension of oxidized CNF. PS-CNF nanocomposites were obtained by heterocoagulation due to the electrostatic interaction between cationic PS latex and anionic CNF. Thermal properties were characterized by DSC and TGA, while morphologies of the nanocomposites were studied by SEM. Electrical resistivity results showed that the percolation threshold in our PS-CNF nanocomposites was below 2 wt% (1 vol%). This low percolation threshold is related to the dispersion, and thus a superior network formation of CNF in PS matrix.