COMPARISON OF CHEMICALLY AND ELECTROCHEMICALLY PREPARED POLYANILINE FILMS .1. ELECTRICAL-PROPERTIES

Thin films (< 200 nm) of chemically prepared polyarniline cast from solutions of formic acid and electrochemically prepared polyaniline films grown on top of the chemical films are characterized electrochemically, by work function changes and by conductivity measurements, The oxidized and reduced films exhibit complex relaxation phenomena over time periods ranging from 1 to 900 h. Water is seen to play a key role in relaxation. An explanation of the relaxation phenomenon is suggested as being a change in the ratio of fully doped conducting material to nonconducting material based on a granular morphology. It is shown that the two polymers are nearly identical chemically and in their behavior with differences being mainly morphological.