Study On Hydrophobicity Of Fluorine-modified Silica Sol Synthesized By Sol-gel Method

Superhydrophobic and thermally stable films were fabricated by sol-gel methodto fluoroalkylsilanized silica sol which was partially embedded bysurface-functionalized silica nanoparticles afterwards. Fluorinated silicananoparticles were synthesized by the hydrolysis of tetraethyl orthosilicate (TEOS)by the assistance of surfactant of cetyltriammonium bromide (CTAB) under basiccondition.(3,3,3-trifluoropropyl) dichloromethylsilane (TFPDClS) was used as thesurface modification fluorinating reagents. Through the adjusting the synthesisconditions, the better particles distribution of fluorinated silica could be obtained.The fluorinated silica nanoparticles were characterized by infrared spectroscopy(FT-IR), scanning electron microscopy (SEM) to test the chemical composition andsurface appearance. The fluorinated silica nanoparticles were used to prepare liquidmarble with water and the stability of the liquid marble was tested by CAmeasurement to investigate the wetting prevention ability of the fluorinated silicananoparticles. It shows that fluorinated silica nanoparticles with better dispersionand wetting prevention ability were fabricated successfully. After the modificationof fluoroalkylsilanization, the shape and size of silica nanoparticles both changed.The fluorinated silica nanoparticles conglutinated to water drop and formed arelative stable liquid marble with a CA of120°and collapsed after70mins.Sol-gel-derived fluoroalkylsilanized silica sol was fabricated by TEOS andTFPDClS under acid and basic conditon respectively before spinned on glasssubstrate. FT-IR, SEM, AFM and CA measurements were carried to test the structure,surface appearance and coatinghydrophobicity. It shows that the surface of coatingwas smooth mostly with some bulging of nano-sized silica network/particles. Thecoating showed long-term hydrophobicity under different temperature, the CA valueof coating of better technology was110oand158orespectively.Superhydrophobic coating comprising fluoroalkyl-surface-functionalized silicananoparticles integrally or sectionally buried into the organo-modified silica sol wascharactered by FT-IR, SEM, AFM and CA tests. The suface composed of(micronano combined) coarse structure were obtained after the addition of nanosilica particles, and the CA value was increased to140oand168obased on differenttechnology respectively. The coating still showed long-term hydrophobicity underdifferent temperature...