Size-controlled SiO2 nanoparticles grafted with reactive fluorosilane for multi-substrate superhydrophobic/antifouling coatings

The construction of superhydrophobic coatings is closely related to both the surface energy of the material and its surface roughness. In this work, a series of nanoparticles were obtained by controllably tuning the nanoparticle size and regulating the surface energy of the bulk materials. The newly synthesized fluorosilanes with different chain lengths were grafted onto the surfaces of multiscale nanoparticles, forming novel nanoparticles with both outstanding hydrophobicity and stability. The microstructures of the nanoparticles were investigated, revealing that uniform nanoparticles with diameters of 150, 250 nm and other sizes could be controllably obtained through the synergistic effects of catalyst concentration and reaction time. A process model correlating particle size with reaction conditions was established, providing a theoretical basis for nanoparticle synthesis. Solid surfaces loaded with the nanoparticles achieved superhydrophobicity, with a maximum water contact angle of 171°. The oil–water separation membrane maintained a separation efficiency higher than 99.2% after six repeated cycles. Thermogravimetric analysis indicated that the materials exhibited good thermal stability, with temperatures corresponding to 10% weight loss exceeding 350°C. This work establishes a theoretical model for the controllable synthesis of uniformly sized silica nanoparticles from the molecular scale, enriching the family of high-performance hydrophobic materials.