INVESTIGATION OF VAPOR-DEPOSITED POLYANILINE THIN-FILMS

X-ray photoelectron spectroscopy (XPS) has been used to investigate th e chemical structure of thin polyaniline films grown using a vacuum ev aporation process that used chemically prepared polyaniline powder as the starting material. Analysis shows that the as-deposited films are in the completely reduced, leucoemeraldine state. This chemical struct ure is contrasted with that of the initial and residual powders, which XPS analysis shows are both in a state close to that of protoemeraldi ne. Thus, the results indicate that the reduction takes place either i n the gas phase or, more likely, as a reaction on the surface of the s ubstrate, but does not occur in the quartz crucible as the initial pow der is being heated. Results are also presented concerning the oxidati on (in pure oxygen and iodine environments) and the protonation (using HCI) of these vapor-deposited polyaniline thin films. Scanning tunnel ing microscopy was also used to examine the in situ growth of submonol ayer coverages of polymer. Evidence for large scale structure growth, possibly resulting from crosslinking of small oligomer components, was observed.