Preparation and characterization of conductive polyaniline/silica hybrid composites prepared by sol-gel process

A method had been developed to cast organic/inorganic hybrid composites by sol-gel process. This procedure was mainly controlled by the pH of mixing c ircumstances of organic/inorganic multicomponent solutions and was attribut ed to the solvent pH. Cast composite from m-cresol solution could not form a uniform hybrid composite film due to the indistinguishable growth and agg regation of silica at pH < 7 in sol-gel processing. On the other hand, hybr id composite cast from N-methyl-2-pyrrolidone (NMP) solution could form a u niform, crack-free film because of its stable silica particle growth accord ing to the mutual repulsion at pH > 7. But bulk conductivity from m-cresol solution was higher than that from NMP solution, which resulted from the se condary-doping effect of the solvent. These conformational changes of the p olymer chain and ability to form hybrid composite film were analyzed by mea ns of Fourier-transform infrared (FTIR), wide-angle X-ray diffraction (WAXD ), microdielectrometer, thermogravimetric analysis (TGA), and conductivity measurements. (C) 2000 Elsevier Science S.A. All rights reserved.