Swift heavy ion irradiation-induced enhancement in structural, conformational and electrical properties of polyaniline nanofibers

Abstract

We report here the irradiation effects of 160 MeV Ni 12+ ion beam on the structural and electrical properties of polyaniline (PAni) nanofibers synthesized by the interfacial polymerization method. The morphological studies show an increase in average diameter of PAni nanofibers upon swift heavy ion (SHI) irradiation. X-ray diffraction results show the amorphous nature of PAni nanofibers and upon SHI irradiation its crystallinity (K) and average crystallite size or extent of order (L) increase with increasing ion fluence. Fourier transform infrared spectroscopy results confirm the formation of PAni and suggest better conjugation length of PAni chains with increasing ion fluence. The ac conductivity follows the universal power law, σ ac = Aω s with (0 < s < 1) and upon irradiation conductivity increases appreciably with fluence. The decreasing behavior of frequency exponent s with temperature suggests correlated barrier hopping transport of charge carriers. Current-voltage characteristics of PAni nanofibers show the non-ohmic behavior and the current increases with increasing ion fluence. Thermogravimetric analysis exhibits enhanced thermal stability of PAni nanofibers upon SHI irradiation.