MORPHOLOGY OF POLYANILINE REDOPED BY KNEADING WITH DODECYLBENZENE SULFONIC-ACID

Polyaniline (PANI) is often doped with an inorganic acid, which can be removed in a dedoping process with ammonium hydroxide and then replac ed with an organic acid in a redoping process. This article shows that both the developing and redoping processes are influenced by the morp hology of the PANI aggregates containing the primary particles. The de tailed morphology develops during the aniline polymerization step and may vary from closed to open structures, depending on the polymerizati on conditions. The redoping process under mild conditions (manual knea ding at 20-60 degrees C) with dodecylbenzene sulfonic acid ( DB SA) le ads to the formation of a DBSA-rich surface layer covering the aggrega tes, which consists of fully doped PANI-DBSA and free DBSA. The thin c onductive PANI-DBSA layers surrounding the aggregates form a continuou s conducting network in compression-molded samples. The depth of penet ration of DBSA molecules into the PANI-base aggregates obviously depen ds on the aggregates structure, that is, a higher DBSA penetration and , thus, a more continuous PANI-DBSA outer layer for the open structure s. (C) 1998 John Wiley & Sons, Inc.