Fabrication of superhydrophobic Cr/PTFE/TiO₂ composite coating via one-step electrodeposition for enhanced buoyancy and anti-biofouling performances

To address the environmental impact of biofouling in marine environments, an efficient one-step electrodeposition method was proposed for producing a superhydrophobic Cr/PTFE/TiO₂ (CPT) coating on Ti-6Al-4V (TC4) surface. A well-defined honeycomb-like microstructure was constructed on the resultant coating. The CPT coating displayed a contact angle of 163.5° and a sliding angle of 3.1°, showing highly improved anti-biofouling and self-cleaning properties. An investigation was conducted into the bouncing process of the water droplet on the CPT coating. The total energy loss and energy recovery coefficient were measured to be 9.5×10^-8 J and 35.4%, respectively. Compared with bare TC4, the CPT coating demonstrated significantly enhanced buoyancy performance, exhibiting a twofold increase in maximum load-bearing capacity. The freezing time of droplets on the CPT coating was delayed to 765s at -10 °C. The prominent mechanical robustness of the coating was confirmed via cross-cut tape peeling, sand impact, and abrasion tests. Moreover, the composite coating exhibited exceptional thermal stability and chemical resistance. The anti-biofouling mechanism of the coating was discussed. The outstanding superhydrophobicity and the intrinsic photocatalytic action of TiO₂ synergized to establish a powerful defense against the adhesion and proliferation of Chlorella and Bacillus sp., thus proposing a viable strategy for anti-biofouling application.