Polypyrrole nanoparticles coated amorphous short silica fibers: Synthesis and characterization

Polypyrrole-coated amorphous silica short fibers (PPy-ASF) were obtained through in situ oxidative polymerization of pyrrole (Py) on the ASF surface by using ferric chloride (FeCl3) as oxidant. These conducting fibers were constituted of PPy particles packed close together to form a continuous conductive layer on the ASF surface which was responsible for electrical conductivity of 0.32 S.cm(-1), similar to that found for pure PPy. The PPy-ASF were blended with polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene copolymer (SEBS) through solution casting at room temperature to form conductive rubbery (SEBS/PPy-ASF) composites. The electrical conductivity and percolation threshold of SEBS/PPy-ASF films were evaluated and also compared with PPy filled SEBS blends (SEBS/PPy) prepared under the same processing conditions. SEBS/PPy-ASF displayed lower percolation threshold and higher electrical conductivity values than those found for SEBS/PPy blends at the same conductive filler concentration. The high PPy-ASF aspect ratio (length to diameter ratio, L:D) and their good electrical conductivity allow production of conductive polymer composites at very low percolation threshold. The results obtained in this study reveal that PPy-ASF materials are promising candidates to be used as conductive filler for developing conducting polymer composites. (C) 2012 Elsevier Ltd. All rights reserved.