Characteristics of the polyaniline films vacuum deposited at a high background pressure

Polyaniline films with different thickness were deposited on unheated glass substrates by vacuum evaporating HCl-doped polyaniline pellets at a high background pressure. Micromorphological, compositional, structural and electrical properties of the films were studied by using field emission scanning electron microscopy, energy dispersive of X-ray spectroscopy, Fourier transform infrared spectroscope and sub-femtoamp source meter. The polyaniline films consist of a large number of flakes. Some flakes are perpendicular to the substrate and they are more in the thick film compared with the thin film. No chlorine is detected in the films. The aromatic structure of polyaniline is retained in all the polyaniline films. However, the polar structure of polyaniline is destroyed in the films. The polyaniline film is in a higher oxidation state compared with the HCl-doped polyaniline pellet. The conductivity of the polyaniline films ranges from 10−8 to 10−9 S/cm and is lower than that of the HCl-doped polyaniline pellet as the starting material. Besides, the conductivity decreases with increasing film thickness.