Preparation of polyaniline conductive composites with diene-rubber or polyphenylacetylene

We describe the preparation of polyaniline (PANI-EB) by aniline oxidation with KIO3 and the purification of the resulting dedoped polymer by an acetone extraction step to eliminate undesired by-products from polyaniline, which could generate some safety concerns in the application and use of PANI. Excellent homogeneous and electrically conducting composite films can be prepared from chloroform solutions of purified PANI doped with camphorsulfonic acid in presence of cis-1,4-polybutadiene as the film-forming agent. These films have been characterized by FT-IR and UV-VIS-NIX spectroscopy. A method to synthesisze PANI directly doped with dodecylbenzenesulfonic acid (DBSA) is also reported. DBSA-doped-PANI was then used to prepare composites with polyphenylacetylene (PPA) by growing homogeneous films from chloroform solution. These films were conductive and were studied by FT-IR and UV-VIS-NIX spectroscopy. In view of the application of these composites as gas sensors or in "electronic noses", a short discussion is presented about the criteria used in the selection of the chemical nature of the host polymer where doped PANI is included to confer electrical conductivity. The interaction between the molecules to be detected and the polymeric sensing surface is discussed in terms of physisorption, chemisorption and charge-transfer-complex formation. Copyright (C) 2001 John Wiley & Sons, Ltd.