Wear behavior of non-hydrogenated and hydrogenated dlc films under protein lubricated condition

Abstract

The differences in structure and wettability of diamond like carbon (DLC) films can influence the outcome of a wear test under protein lubricated condition. The aim of this study is to analyze the wear behavior of different structure of DLC films (ta-C and a-C:H) under bovine serum albumin as an attempt to simulate synovial fluid protein in artificial joints. The hardness, structure and surface wettability of films were investigated. Fourier transform infrared spectroscopy (FT-IR) was employed to investigate changes of protein conformation on the film surfaces after incubation for 24 h at 37°C. The wear behavior of DLC films and its counterpart, ultra-height molecular weight polyethylene (PE) were assessed by reciprocating tribo tester. There is a correlation between surface wettability, protein absorption and wear behavior, and in this study, it has been found that the surface of a hydrophobic a-C:H film tends to bind more protein due to the contribution of hydrogen bonds. As a result, the wear rate of PE against a-C:H film is found to be low due to adsorbed protein acts as a lubricant film and protects the surface from wear.