Tailoring Biotribological Performance of Polytetrafluoroethylene Nanocomposites through Control of Diameters and Aspect Ratios of In Situ Filled Hydroxyapatite Nanowires

Excellent biocompatibility and biotribological performance are necessary for artificial acetabular cups in total hip replacement. Herein, polytetrafluoroethylene (PTFE) nanocomposites are fabricated via an in situ filling of hydroxyapatite nanowires. The resulting nanocomposites are characterized and evaluated by sliding friction against a high-speed steel ring in the presence of simulated body fluid. Markedly enhanced hydrophobicity, heat resistance, and stiffness are observed for the fabricated nanocomposites in comparison with the matrix PTFE. The ethanol/water ratios for the in situ fabrication of the nanocomposites showed a predominant role in the diameters and aspect ratios of the hydroxyapatite nanowires filled in the nanocomposites. This might be related to the competition between the nucleation and growth of the hydroxyapatite crystals under applied synthetic conditions because the concentration of ethanol can influence the size and morphology of the oleic acid micelles. Furthermore, the diameters and aspect ratios of the nanofiller are found a decisive role in the tribological performance of the resulting PTFE nanocomposites, and those fabricated using a low ethanol/water ratio showed an enhanced diameter and aspect ratio and remarkable improvement in biotribological performance. The fabrication method is believed promising for the design and controllable synthesis of artificial acetabular cups or other artificial tissues.