Preparation of g-CN/TNTs/CNTs Photocatalytic Composite Powder and Its Enhancement of Antifouling Performance of Polydimethylsiloxane Coatings.

Semiconductor photocatalytic materials have shown potential in the field of antifouling due to their good antibacterial properties, stability, and nontoxic properties. It is an effective way to use them to improve the static antifouling performance of silicone antifouling coatings. g-CN/TNTs/CNTs (CNTC) photocatalytic composite powders were prepared and introduced into polydimethylsiloxane (PDMS) coatings to enhance their antifouling performance. Firstly, g-CN/TNTs with heterostructure were thermally polymerized by urea and TiO nanotubes (TNTs), and then g-CN/TNTs and multi-walled carbon nanotubes (CNTs) were composited to obtain CNTC. Finally, CNTC was added into PDMS to prepare g-CN/TNTs/CNTs/PDMS (CNTC/P) composite antifouling coating. The results showed that CNTC successfully recombined and formed a heterostructure, and the recombination rate of photogenerated carriers decreased after recombination. The addition of CNTC to PDMS increased the hydrophobicity and roughness while reducing the surface energy (SE) of the coatings. CNTC could effectively improve the anti-attachment performance of PDMS coatings to bacteria and benthic diatom. The bacterial attachment rate (A) and benthic diatom attachment rate (A) of CNTC/P-20 were, respectively, 13.1% and 63.1%; they are much lower than that of the coating without photocatalytic composite powder. This coating design provides a new idea for developing new "efficient" and "green" photocatalytic composite antifouling coatings.