Implications of using m-cresol in the Langmuir–Blodgett processing of polyaniline

Abstract

The use of m-cresol for the Langmuir–Blodgett (LB) processing of polyaniline has been investigated, in particular for probing possible secondary doping processes in LB films. Langmuir monolayers and LB films of polyaniline and polyaniline–cadmium stearate composites have been obtained with the use of camphor sulfonic acid (CSA) both in the presence and absence of m-cresol in the spreading solution. Expanded monolayers with higher molecular areas have been observed upon employing m-cresol. The UV-vis spectral changes for the polyaniline LB films caused by m-cresol were shown to depend both on the preparation conditions and on the doping state of the monolayer. Such effects are likely to originate from changes in molecular conformation since m-cresol is not retained in the transferred film. In addition, processing with m-cresol brought no change to the electrical conductivity nor to the stacking order of cadmium stearate domains in the transferred LB films.