Measurement of the extent of impurity incorporation during potentiostatic and cyclic potential sweep depositions of polyaniline

Abstract

The difference between potentiostatic deposition and cyclic potential sweep deposition (CPS) of polyaniline (PANi) is rationalized on the basis of factors in control of the growth process. The removal of unreacted oxidized PANi in the pernigraniline form during deposition is crucial to the formation of quality films. An expedient removal of the deposition is crucial to the formation of quality films. An expedient removal of the oxidized species maintains good conductivity in the film, reduces the retention of hydrolysis products and enables thicker films with better morphology and structural integrity to be grown. In potentiostatic deposition, the oxidized species is removed by its reactions with aniline and water, albeit somewhat ineffectively. The latter reaction is deleterious as it leads to polymer degradation and the incorporation of hydrolysis products in the film. CPS deposition provides an additional means of removal of unreacted oxidized species through the imposition of the cathodic scan. This is conceived as a more important functionality of CPS than its ability to keep the polymer under a highly oxidized state for shorter time. © 1993.