Complete filling of Cu2O into high-aspect-ratio TiO2 nanotube arrays with strong adhesion on the titanium for long-lasting anti-fouling performance

Titanium, known for its high strength-to-weight ratio and excellent corrosion resistance, has great potential for marine engineering application. However, due to its biocompatibility, titanium is highly susceptible to undesirable biofouling in the marine environment. In this study, we developed a long-lasting anti-fouling surface by completely filling Cu 2 O into TiO 2 nanotube arrays with a high aspect ratio of 132 on the titanium. The interfacial bonding strength between the high-aspect-ratio TiO 2 nanotube arrays and the titanium was subsequently enhanced by a factor of 7.98 through a two-step post-anodization and annealing treatment, which was sufficient to resist the stripping effect of the subsequent electrochemical filling of Cu 2 O. Then, the reinforced high-aspect-ratio TiO 2 nanotube arrays were completely filled with Cu 2 O by a two-step electrochemical filling strategy, resulting in a loading amount of Cu 2 O up to 1.5 mg/cm 2 on the titanium and inhibiting its burst release in the seawater with a release rate of less than 10 μ g/(cm 2 ·d). Compared to titanium, this nanocomposite structure maintained over 99 % anti-adhesion ratio against N . incerta for up to 217 days and resisted biofouling for more than 1 month in the actual marine environment. This in-situ prepared, cost-effective, and highly-efficient anti-fouling titanium surface provides a novel strategy for large-scale applications of titanium in the marine engineering.