Residual water and electrical properties of polyaniline

Summary form only given. The work aims to study the mechanism of interaction between water molecules and polyaniline (PANI) backbone as an important constituent of acid-base transformations ensuring good conductive properties of PANI. Experiments have been made using chemically synthesized emeraldine base subjected to different chemical treatments and aging procedures. Thermogravimetric measurement have shown that water content in polymeric matrices may amount up to 20-25 wt.% with two distinguished reversible absorbance states of water molecules. Weakly bond water (3-5 kcal/mol) is incorporated into PANI from ambient atmosphere and could be eliminated by drying at room temperature in vacuum or nitrogen atmosphere. T´here also exists second type of water bonding with increased energy (15-18 kcal/mol). Upon heating of the PANI without direct contact with atmosphere weakly-bonded water molecules may to be transformed into the strongly bonded ones. It is suggested that both types of bonded water molecules input into the formation of three-dimensional conductive network of PANI through the mechanism similar to acid doping process. Basing on electrical properties of the samples containing different amounts of water the possible ways to increase the conductivity of PANI are discussed.