On the optical and electrical properties of rf and a.c. plasma polymerized aniline thin films

Abstract

Polyaniline is a widely studied conducting polymer and is a useful material in its bulk and thin film form for many applications, because of its excellent optical and electrical properties. Pristine and iodine doped polyaniline thin films were prepared by a.c. and rf plasma polymerization techniques separately for the comparison of their optical and electrical properties. Doping of iodine was effected in situ. The structural properties of these films were evaluated by FTIR spectroscopy and the optical band gap was estimated from UV-vis-NIR measurements. Comparative studies on the structural, optical and electrical properties of a.c. and rf polymerization are presented here. It has been found that the optical band gap of the polyaniline thin films prepared by rf and a.c. plasma polymerization techniques differ considerably and the band gap is further reduced by in situ doping of iodine. The electrical conductivity measurements on these films show a higher value of electrical conductivity in the case of rf plasma polymerized thin films when compared to the a.c. plasma polymerized films. Also, it is found that the iodine doping enhanced conductivity of the polymer thin films considerably. The results are compared and correlated and have been explained with respect to the different structures adopted under these two preparation techniques.

Facile and novel route for preparation of nanostructured polyaniline (PANi) thin films

“…12 shows the variation of (aht) 2 with incident photon energy (ht), the band gap, E g , was determined. The band gap was found to be 3.40 eV which is lower than earlier reported by Sajeev et al (2006) (3.65 eV) and higher than earlier reported by Pawar et al (2011) (2.54 eV), showing a blue shift of 0.86 eV. This is attributed to the size quantization of nanofibered polyaniline thin films.…”

Molecular iodine/polymer complexes

“…The iodinedoping of alternating current (ac) plasma polymerized aniline thin films was also reported by Mathai et al [236] and Sajeev et al [237]. Iodination techniques included the iodine chamber method (iodine crystals were placed in a glass beaker and the films to be doped were kept above this glass beaker) and in situ iodine doping (both monomer and the dopant iodine were sprayed simultaneously into the plasma zone).…”

A Possibility for Construction of an Iodine Cleaning System Based on Doping for π-Conjugated Polymers

“…Therefore, the donor-accepter interactions between -conjugated polymers (polyacetylene, polythiophene, polypyrrole, polyphenylene, and their derivatives) and iodine can be considered as a useful method for accumulation of iodine. Iodine doping in PANI has been reported in previous studies [7][8][9][10]. In this study, a possibility of a PANI/pulp composite sheet for iodine absorption through vapor phase doping of iodine is investigated.…”