ELECTROCHROMIC PROPERTIES OF VACUUM-EVAPORATED POLYANILINE FILMS

The emeraldine base was deposited on SnO2 glass substrates in vacuum b y thermal evaporation in the temperature range 275-325 degrees C. The as-deposited films differ dramatically from the native polyaniline and are formed by the reduction of oligoanilines with molecular weight ab out 1500. The cycling acid-base treatment of vacuum thermally deposite d films gives rise to formation of polyaniline-like material. The prop erty restoration of sublimed films is apparently determined by the res toration of 3D associates in the film body. Molecular structure defect s in vacuum-deposited films are responsible for the lower rates of col oration/decoloration, the lower contribution to imine formation and ir reversible injection of anodic charge under the first oxidation/reduct ion cycle. The lower imine concentration in sublimed polyaniline films results in more coloration/decoloration cycles.