Studies on potentiostatically deposited poly(<i>o</i>-toluidine) and poly (<i>m</i>-toluidine) films: A comparative aspect

Abstract

The optical, thermal and morphological properties of potentiostatically deposited poly (<em>o</em>-toluidine) a nd poly (m-toluidine) have been investigated and compared with each other. The effect of monomer concentration and pH of solution on different properties of films has been reported. The formation of conducting emeraldine phase having peak at ~860 nm is found to be more predominant in the case of poly(<em>o</em>-toluidine) as compared to that observed in poly(<em>m</em>-toluidine). Further, the optical spectra recorded as a function of pH of solution show pronounced formation of additional phases in poly(<em>m</em>-toluidine) films in relation to that noticed in the poly (<em>o</em>-toluidine) films. These differences are explained on the basis of polymerization mechanism and rate of deposition of the two polymers. The thermograms also exhibit variation in terms of the number of steps involved in decomposition as well as final decomposition temperature. These differences might be due to the variation in the fraction of different phases of polymer in each case and also to the molecular weight of the different fragments. The morphology of the polymer, however, does not reveal any difference except the appearance of fibrillar morphology at acidic pH (-1.49) which undergoes transition to granular type at pH 4.07.