Range Of Water Contact Angles Research Articles

Silicon dioxide and titanium dioxide films show varying biocompatible characteristics when used as a passive biocompatible coating for an implant. The difference in their behaviour in biological environment is due to many factors like surface energy, surface charge, semi-conducting nature, surface roughness, coefficient of friction, etc. Surface wettability of the film plays a key role in determining the biocompatible characteristics of the film. In this work films with a range of water contact angle have been deposited on 316L stainless steel with enhanced adhesion strength and good stability in biological media. SiOx, TiOx and SiO-TiO mixed oxide films have been deposited by PECVD for this purpose. The water contact angle of the films ranges from 105° for polymer-like films to 24° for titanium oxide films. Intermediate values of contact angle of 60° for SiOx down to 38° could be obtained from mixed oxide films by controlling the precursor ratio and RF power. The structure of the film is analysed by FT-IR spectroscopic measurements. The adhesion strength is measured for various pre-treatment times by using a pull-off adhesion tester. The stability of the films in biological media is analysed by using an optical microscope. The adhesion and stability are improved by the combination of pre-treatment and layered film deposition.

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