Formation and characterisation of nanoporous TiO2 layers on microroughened titanium surfaces by electrochemical anodisation

Nanoporous titanium dioxide (TiO2) layers were successfully formed by an electrochemical anodisation method on microroughened titanium (Ti) surfaces in fluoride containing aqueous electrolyte. Microroughened Ti surfaces were produced by sandblasting with Al2O3 particles of 50 μm in diameter and acid-etching in a blend of HCl/H2SO4 solution. The surface morphology, topography and chemical composition of the specimens were analysed by scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. The surface roughness and the wettability of treated Ti surfaces were measured using profilometry and a contact angle measurement system, respectively. With anodising of sandblasted-/acid etched surfaces, micrometre- and nanometre-scale textures on titanium specimens were created. Results showed that these developed nanoporous-microroughened surfaces exhibited lower contact angle values than the other treated Ti surfaces. The sandblasted/acid-etched/anodised Ti specimen had a surface morphology with distinctively formed hills and valleys and higher surface roughness than the other anodised specimens. This study indicated that nanoporous TiO2 structures fabricated on microroughened Ti can be an effective way to modify the titanium surfaces for the future development of implant applications.