Effect of Ni2+ as a codopant on the structure, morphology, and conductivity of nanostructured polyaniline

Abstract

AbstractOne‐dimensional nanostructures of polyaniline (PANI) doped with (1S)‐(+)‐10‐camphorsulfonic acid (D‐CSA) alone and with NiCl2 as a codopant were synthesized via in situ polymerization. PANI nanofibers with diameters of about 200 nm were formed when PANI was doped with D‐CSA only. When NiCl2 was added as a codopant, the morphology of PANI obviously changed. The effects and related mechanisms were investigated by Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, inductively coupled plasma–atomic emission spectroscopy, and X‐ray diffraction, and the results indicated that Ni2+ destroyed the micelles' structure by chemical conjunction with SO3H groups in camphorsulfonic acid (CSA) molecules, which were the key component in forming the CSA–aniline micelles. The combination between Ni2+ and SO in CSA with a lower addition of Ni2+ led to a reduction of CSA doping to PANI, but a higher loading of Ni2+ brought about the direct doping of Ni2+ to PANI, which caused a higher degree of doping and oxidation. The conductivity of PANI increased almost linearly with increasing Ni2+. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011