In Situ Rapid Preparation of the Cu-MOF Film on Titanium Alloys at Low Temperature

Titanium alloys are widely used in marine environments and medical fields due to their excellent corrosion resistance and high specific strength. However, their good biocompatibility can lead to severe biofouling, thereby limiting their effectiveness. To inhibit biofouling on the surface of titanium alloys, this study proposes an antifouling solution, which involves the in situ preparation of Cu-MOF film on titanium alloys by leveraging the antibacterial properties of Cu ions. Here, the dense and stable TiO₂ film on the surface of Ti-6Al-4V titanium alloy was removed by alkali-heat treatment; meanwhile, a porous surface structure was simultaneously obtained where OH^- ions were retained. In the subsequent step, the retained OH^- ions in the pores attracted Cu²⁺ ions in solution to form Cu(OH)₂ in the pores, providing active sites for the formation of Cu-MOFs. Subsequently, Cu(OH)₂ reacted with organic ligand (1,3,5-benzenetricarboxylic acid, BTC) at room temperature to form Cu-MOFs in the pores, which then grew quickly to cover the alkali-heat-treated surface within 1 h. The formation mechanism of Cu-MOF film on Ti-6Al-4V was elucidated, which provides a reference for designing and preparing multifunctional MOF film in situ on titanium alloys. The stability of in situ-grown Cu-MOF samples and their inhibitory effects on bacteria and microalgae have also been verified. The results indicate that although the stability of Cu-MOFs is relatively poor, their bactericidal and algicidal effects are extremely significant, suggesting that this material has significant potential for short-term applications that require high antibacterial performance.