Spectral, thermal and electrical properties of the derivatives of polyanilines

Abstract

Six poly-<em>o</em>-alkyl(methyl, ethyl, propyl)- and poly-<em>o</em>-alkoxy(methoxy, ethoxy, propoxy)anilines have been characterized. Thermograms show that these polymers lose water, low molecular weight oligomers, alkanes, (or alkoxy groups in polyalkoxyanilines) successively with increase in temperature and finally leave a residue of unburnt carbon. The UV-vis spectra show an increase in the band gap energy with increase in the length of the side chain. The coordinating solvents-NMP and DMF-turn these into rod-like forms whereas a non coordinating solvent, CH₂Cl₂ keeps them in the coiled form. The cyclic voltammograms show that with the increase in the length of the side chain, the half wave potential for the conversion of their most reduced forms into the semiquinone radical cation increases whereas that for the conversion of the radical cation to their most oxidized form decreases because of the instability of the radical cation.