Investigations of the hydrophobic and scratch resistance behavior of polystyrene films deposited on bell metal using RF-PACVD process

Polystyrene films are deposited on bell metal substrates using radiofrequency plasma assisted chemical vapor deposition (RF-PACVD) process. The deposition of polystyrene film is carried out at working pressure of 1.6 × 10⁻¹ mbar and in the RF power range of 20-110 W. The hydrophobic and mechanical behaviors of the polystyrene films are studied as a function of RF power. The chemical compositions and surface chemistry of the polystyrene films are investigated using Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). It is revealed that enhanced cross-linked chemical structure and higher loss of oxygen by peroxy polystyryl radical with increasing RF power results in the formation of polystyrene films with more hydrophobic and scratch resistance behavior. However, extensive destruction of cross-linked chemical structure due to high energetic ion bombardment tends to decrease the hydrophobic and scratch resistance behavior of the polystyrene film deposited at RF power of 110 W. Atomic force microscopy (AFM) images show quite uniform and crack free surfaces of the polystyrene films having rms roughness in the range of 0.35-0.87 nm. Attempts are made to correlate the characterization results with the parameters that are used for thin film depositions.