Fabrication and characterization of haemocompatible TiO2 films by thermal and anodic oxidation techniques

VERA, M.L.; ARES, A.E.; MARIO ROBERTO ROSENBERGER; SCHVEZOV, C. E.

25 al 27 de agosto de 2009, Rosario, Santa Fe, Argentina.

Taller; 1º Taller de Órganos Artificiales, Biomateriales e Ingeniería de Tejidos” (BIOOMAT); 2009

Asociación Argentina de Biomateriales

A protective titanium dioxide (TiO2) film covers the surface of the titanium (Ti) and its alloys in ambient conditions. This natural oxide is 2 to 7 nm thick, and it is one of the main responsible for the success of titanium alloys as an implantable material. Thicker TiO2 films can be produced on a titanium alloy, as the Ti-6Al-4V, by thermal or anodic oxidation. In this study, TiO2 films on Ti-6Al-4V as substrate were produced by thermal and anodic oxidation techniques and compared. On one hand, TiO2 films produced by thermal oxidation were growth in air atmosphere at 500 and 600ºC during different times of process: 0.5, 1, 2 and 24 hour. On the other hand, TiO2 films produced by anodic oxidation technique were growth in a 1M H2SO4 solution at voltages from 10V to 100V, during 1 min. The surface characterization was performed by optical and scanning electron microscopy, and by X-ray diffraction (XRD) operated with glancing angle geometry with an angle of incidence of 1°. Films of different colours were obtained, with thickness ranged from 20 to 200 nm. Smooth and compact films were obtained at time processes below 1 hour by the thermal technique and at voltages below 50V by the anodic technique. Porous films were obtained at long times and voltages larger than 50V. Crystalline phases of TiO2 (anatase and rutile) were obtained by thermal treatment and by the anodic treatment at high voltages. The films produced at low voltages are amorphous; these amorphous films could be transformed to crystalline by a thermal treatment with a slightly increase of the thickness and no change in the roughness. These smooth and crystalline films are suitable to biomedical applications and devices in contact with blood, were haemocompatibility are necessary.