Vapor deposited polyaniline films on Cu(110) have been characterized using high resolution electron energy loss spectroscopy. Ultrathin films (less than or equal to 100 Angstrom) were found to exist in an oxidation state close to that of the starting emeraldine powder. After doping with HCl, the films exhibited plasmon excitations in the far-ir, suggesting that they are highly crystalline and possess electrical conductivities higher than those of HCl doped emeraldine films produced by wet-chemical deposition techniques, In contrast, thicker vapor-deposited films (greater than or equal to 1000 Angstrom) were found to be highly reduced, less crystalline, and exhibited electrical conductivities lower than those of the thinner films upon doping. These results suggest that the interactions of emeraldine with a metal surface can play an important role in determining the chemical, structural, and electronic properties of polyaniline films near the polymer-substrate interface.