Thickness dependent structural and surface properties of plasma polymerized N-benzylaniline thin films

Abstract

Thickness dependent structural, surface morphological, topographical and compositional studies have been done on the plasma polymerized N-benzylaniline (PPNBA) thin films, where the plasma is obtained by a parallel plate capacitively coupled glow discharge system under AC of frequency 50 Hz. From the X-ray diffraction studies, it is confirmed that the PPNBA thin films are amorphous in nature. The chemical structure of the PPNBA films is moderately changed from that of the monomer owing to the elimination of some benzyl groups, however, becomes conjugated due to C=C stretching of the quinoid and benzenoid units. The PPNBA films contain mostly carbon and nitrogen, which is confirmed by the energy-dispersive X-ray analysis. However, the presence of oxygen is considered to be incorporated from the reactor atmosphere. The surface morphologies of the PPBNA thin films of various thicknesses are mosaic-like structure, which is formed by the uniform distribution of unequal nanosized clusters over the smooth background of the film surface. The average roughness and root mean square roughness of the surface of the PPNBA thin films are found to be in the order of pm. The increase in the surface roughness is compatible with the increase in the cluster density, which is evidenced in the field-emission scanning electron microscopy observations.