Influence of surface wettability on the tribological properties of laser textured Co-Cr-Mo alloy in aqueous bovine serum albumin solution

Surface wettability behaviors of three kinds of laser textured Co-Cr-Mo alloy surfaces (arrays of circular, triangular and square shape dimples) were evaluated in aqueous bovine serum albumin (BSA) solution. The tribological properties of laser textured Co-Cr-Mo alloy were investigated by pin-on-disc reciprocating tribometer under BSA lubrication. The wetting surfaces ranging from superhydrophilic (CA = 21.5°) to superhydrophobic (CA = 142.2°) were obtained by dual/combined surface modification including laser surface texturing (LST) and further fluoro-alkyl silane (FAS). It was found that surface wettability behaviors of Co-Cr-Mo alloy surfaces were closely related to their tribological behaviors in BSA solution. Results showed that the contact angle of circular dimple was the most stable, sliding time of the friction pair reaching steady state stage was shortest and coefficient of friction was minimum among three regular layout shapes of dimples during the tribological tests. It suggests that the combined surface modification of LST and FAS is a promising method to improve the tribological performances and prolong the service life of Co-Cr-Mo orthopedic implants.