A Nanoindentation Approach for Time-Dependent Evaluation of Surface Free Energy in Micro- and Nano-Structured Titanium

Surface free energy (SFE) of titanium surfaces plays a significant role in tissue engineering, as it affects the effectiveness and long-term stability of both active coatings and functionalization and the establishment of strong bonds to the newly growing bone. A new contact-mechanics methodology based on high-resolution non-destructive elastic contacting nanoindentation is applied here to study SFE of micro- and nano-structured titanium surfaces, right after their preparation and as a function of exposure to air. The effectiveness of different surface treatments in enhancing SFE is assessed. A time-dependent decay of SFE within a few hours is observed, with kinetics related to the sample preparation. The fast, non-destructive method adopted allowed for SFE measurements in very hydrophilic conditions, establishing a reliable comparison between surfaces with different properties.

Automated summary

Surface free energy (SFE) of titanium surfaces plays a significant role in tissue engineering, affecting the effectiveness and long-term stability of active coatings and functionalization as well as the establishment of strong bonds to newly growing bone. This study used a high-resolution non-destructive elastic contacting nanoindentation method to investigate the SFE of micro- and nano-structured titanium surfaces, both immediately after preparation and after exposure to air. The effectiveness of different surface treatments in enhancing SFE was evaluated. The study observed a time-dependent decay of SFE within a few hours, with kinetics related to sample preparation. The fast, non-destructive method allowed for accurate measurement of SFE in very hydrophilic conditions, allowing for reliable comparison between surfaces with different properties.