ELECTROCHEMICAL POLYMERIZATION OF POLY(O-ANISIDINE) THIN-FILMS - EFFECT OF SYNTHESIS TEMPERATURE STUDIED BY CYCLIC VOLTAMMETRY

The effect of temperature on the electrochemical synthesis of poly(o-a nisidine) (POA) thin films has been investigated. The POA films were s ynthesized electrochemically under cyclic voltammetric conditions in a queous solutions of H2SO4 at various temperatures between -6 degrees C and 40 degrees C. These films were characterized by cyclic voltammetr y (CV), UV-visible spectroscopy and scanning electron microscopy (SEM) . It has been found that the rate of polymer formation depends on the synthesis temperature and is highest at 15 degrees C. The optical abso rption spectra indicate a major peak at about 800 nm and a shoulder at about 440 nm independent of the synthesis temperature. The peak at ab out 800 nm corresponds to the presence of the emeraldine salt phase of POA, while the latter may be attributed to the formation of radical c ations. The absorbance and width of the peak at about 800 nm is observ ed to increase at low synthesis temperatures. The POA film synthesized at 15 degrees C shows predominant formation of the emeraldine salt ph ase of POA. The surface morphology as revealed by SEM, is observed to depend on the synthesis temperature, and is caused by different rates of polymer formation at different temperatures. (C) 1998 SCI.