Surface energy of the plasma treated Si incorporated diamond-like carbon films

Surface energy and surface chemical bonds of the plasma treated Si incorporated diamond-like carbon films (Si-DLC) were investigated. The Si-DLC films were prepared by r.f. plasma assisted chemical vapor deposition using benzene and diluted silane (SiH4/H2 = 10:90) as the precursor gases. The Si-DLC films were subjected to plasma treatment using various gases like N2, O2, H2 and CF4. The plasma treated Si-DLC films showed a wide range of water contact angles from 13.4° to 92.1°. The surface energies of the plasma treated Si-DLC films revealed a high polar component for O2 plasma treated Si-DLC films and a low polar component for CF4 plasma treated Si-DLC films. The CF4 plasma treated Si-DLC films indicated the minimum surface energy. X-ray photoelectron spectroscopy (XPS) revealed that the polarizability of the bonds present on the surface explains the hydrophilicity and hydrophobicity of the plasma treated Si-DLC films. We also suggest that the O2 plasma treated surface can provide an excellent hemocompatible surface from the estimated interfacial energy between the plasma treated Si-DLC surface and human blood.