title: Tribological characterization of a biocompatible thin film of UHMWPE on Ti6Al4V and the effects of PFPE as top lubricating layer.
abstract: Ultra-high molecular weight polyethylene (UHMWPE) thin film was coated onto Ti6Al4V alloy specimens using dip coating method. Tribological performance of this coating (thickness of 19.6 ± 2.0 μm) was evaluated using 4 mm diameter Si(3)N(4) ball counterface in a ball-on-disk tribometer. Tests were carried out for different normal loads (0.5, 1.0, 2.0 and 4.0 N) and rotational speeds of the disk (200 and 400 rpm). UHMWPE coating formed in this study exhibits high hydrophobicity with water contact angle of 135.5 ± 3.3° and meets the requirements of cytotoxicity test using the ISO 10993-5 elution method. This coating shows low coefficient of friction (0.15) and high wear durability (>96,000 cycles) for the tested conditions. PFPE overcoat on UHMWPE has further increased the wear durability of UHMWPE coating as evaluated at even higher rotational speed of 1000 rpm.
authors.affiliation: Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore.
authors.forename: Bharat
authors.initials: B
authors.lastname: Panjwani
authors.forename: Nalam
authors.initials: N
authors.lastname: Satyanarayana
authors.forename: Sujeet K
authors.initials: SK
authors.lastname: Sinha
mesh_terms: D000497:Alloys; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000633:toxicity; D004987:Ethers / Q000737:chemistry*; D005347:Fibroblasts / Q000187:drug effects; D005466:Fluorocarbons / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D054327:Lubricants / Q000737:chemistry*; D008422:Materials Testing; D055595:Mechanical Phenomena; D051379:Mice; D011095:Polyethylenes / Q000737:chemistry*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; D004987:Ethers; D005466:Fluorocarbons; D054327:Lubricants; D011095:Polyethylenes; C078113:perfluoropolyether; C111601:ultra-high molecular weight polyethylene; C031462:titanium alloy (TiAl6V4); D014025:Titanium