Conductive blends of polyaniline with plasticized poly(methyl methacrylate)

Polyaniline (PANI) protonated with camphorsulfonic acid (CSA) and three dif ferent poly(alkylene phosphates) (PAPs) (where alkylene = pentylene, hexyle ne, or nonylene) was used in the fabrication of conductive polyaniline-poly (methyl methacrylate) (PMMA) blends. The lowest percolation threshold (f(p) , = 0.041 wt %) was obtained for the PANI(CSA)(0.5)-PMMA blend plasticized with 35 wt % of dibutyl phtalate (DBPh). This blend is also very resistant against the deprotonation of its conductive phase in basic solutions of pH = 9. In the case of blends prepared with the use of PAPs as PANI dopants, t he percolation threshold strongly depends on the length of the hydrophobic spacer (alkylene group) in the dopant. The percolation threshold decreases in the order PPP > PHP > PNP, whereas the resistance against deprotonation in basic solutions decreases in the following inverse order: PNP > PHP > PP P. This last observation can be rationalized by increasing contribution of hydrophobic segments in the polymeric dopant, when going from PPP to PNP, w hich renders polyaniline more resistance toward the penetration by aqueous basic solutions. (C) 1999 John Wiley & Sons, Inc.