Our research group developed a novel nano-pitted (NP) TiO2 surface on grade 2 titanium
that showed good mechanical, osteogenic, and antibacterial properties; however, it
showed weak hydrophilicity. Our objective was to develop a surface treatment method
to enhance the hydrophilicity of the NP TiO2 surface without the destruction of the
nano-topography. The effects of dilute and concentrated orthophosphoric (H3PO4) and
nitric acids were investigated on wettability using contact angle measurement. Optical
profilometry and atomic force microscopy were used for surface roughness measurement.
The chemical composition of the TiO2 surface and the oxidation state of Ti was investigated
using X-ray photoelectron spectroscopy. The ccH3PO4 treatment significantly increased
the wettability of the NP TiO2 surfaces (30°) compared to the untreated control (88°).
The quantity of the absorbed phosphorus significantly increased following ccH3PO4
treatment compared to the control and caused the oxidation state of titanium to decrease
(Ti4+ → Ti3+). Owing to its simplicity and robustness the presented surface treatment
method may be utilized in the industrial-scale manufacturing of titanium implants.