Antifouling Performance of Poly(dimethyl-methylphenyl-methyltrifluoropropyl)siloxane Coatings Modulated by Titanium Dioxide Structure and Silicone Oil Leaching Kinetics

Leaching of incorporated silicone oil (SO) from poly(dimethyl-methylphenyl-methyltrifluoropropyl)siloxane (PDPFS) coatings has been proven to be the main driving force of their excellent fouling-release efficacy against marine bacteria and Navicula tenera, surpassing the effects of surface free energy or roughness. This study proposes an approach to control the SO leaching behavior of PDPFS coatings by altering their internal filler structure, thereby modulating their antifouling performance. Five anatase titanium dioxide (TiO 2 ) structures (microparticles, nanoparticles, photocatalytic particles, nanofibers, and nanotubes) were incorporated alongside methyl or phenylmethyl SO (MSO/PSO) into PDPFS-based coatings. The findings of the study establish distinct filler structure–property relationships. High-aspect-ratio TiO 2 (nanofibers/nanotubes) yielded a lower Young’s modulus and created continuous interfacial channels, which synergistically accelerated SO leaching and maximized its dynamic surface coverage–a process quantitatively described by the Higuchi model. A multistage leaching mechanism of “Homogeneous dispersion–Interfacial enrichment–Channelized migration–Surface leaching” is proposed. The results of the study support a fundamental shift in design strategy, highlighting that control of the internal filler structure can modulate SO leaching kinetics, providing a powerful paradigm for developing high-performance, sustainable fouling-release coatings.