Preparation And Self-cleaning Property Of Dynamically Hydrophobic-oleophobic Surfaces

Due to its unique anti-wetting behavior and wide application prospects in self-cleaning and other fields,dynamically hydrophobic-oleophobic surfaces have become an important topic in the development of new materials.Based on the three different strategies,this work focus on the preparation and properties of dynamically hydrophobic-oleophobic surfaces,and attempted to solve some problems in this field.1.1H,1H,2H,2H-perfluorooctyltriethoxysilane and 1H,1H,2H,2H-perfluorodecyltriethoxysilane were grafted to Ti O₂ nanoparticles to form modified Ti O₂?TO-X and TD-Y?,and FT-IR and TGA were used to characterize the effect of grafting conditions?concentration and type of fluorosilane?on the grafting density.The TO-X and TD-Y dispersions with different grafting densities were sprayed on the substrates to form hydrophobic-oleophobic surfaces with specific re-entrant structure?TOS-X and TDS-Y?.The contact angles?CA?and sliding angles?SA?of droplets with different surface energy on TOS-X and TDS-Y were measured.Among them,the TDS-80had the best anti-wetting property,the water,ethylene glycol and oleic acid CA values were 159.94°,143.48°and 134.55°,SA values were 1.34°,15.86°and 26.48°,and CAH values were 5.22°,19.57°and 28.90°,respectively.Further tests were done on the bounding performance of water droplets on TDS-Y surfaces,storage stability of TOS-80and TDS-80 and the self-cleaning property of TDS-80 applied to common substrates.Finally,the possible mechanism of the influence of grafting density on surface wettability and the role of photocatalytic Ti O₂ nanoparticles in maintaining and restoring the lyophobicity were discussed.2.Silicone/Ti O₂?ST_x?surfaces were prepared from liquid silicone and Ti O₂nanoparticles followed by the investigation of the relationship between surface morphology and wettability.Then the dimethylsilicone used as lubricant was infused to ST_1.0 to form SLIPS_y?Slippery lubricant-infused porous surface?followed by the measurement of water and oleic acid CA and SA.Among them,the SLIPS₁₀₀ surface had excellent dynamically hydrophobic-oleophobic property with water and oleic acid SA values being 1.64°and 2.11°,respectively.The wettability of ethanol aqueous solutions with different volume fractions and distilled water at different temperatures on ST_1.0and SLIPS_ywas compared.Further,the effect of the dimethylsilicone viscosity on the shear and thermal stability for SLIPS_y was studied,showing better shear and thermal stability when the lubricant viscosity was up to 100 m Pa·s,while the sliding speed of droplets on SLIPS_y surface decreased with the increase of lubricant viscosity.It was found that SLIPS_y showed good self-repairing and outstanding self-cleaning for liquid contaminants with different surface energies,temperature and p H values.Finally,the possible mechanism of the influence of lubricant viscosity on the shear and thermal stability was discussed.3.Using non-stoichiometry two-component liquid silicone as precursor,the slippery liquid-like polymer-grafted surface?SLPGS?was fabricated by hydrosilylation between the residual Si-H bond in precursor and monovinyl terminated polydimethylsiloxane?MV-PDMS?,showing transparent and dynamically hydrophobic-oleophobic properties.Then,FT-IR,XPS,FE-SEM and AFM were used to characterize the composition,structure and morphology of SLPGS.The CA,SA and CAH values of droplets with different surface energy on SLPGS were measured.Water CA ranged from 107.86°to109.10°,and n-hexadecane CA ranged from 14.26°to 18.30°,showing static hydrophobicity and oleophilicity.Water SA ranged from 1.85°to 2.82°and water CAH ranged from 176°to 4.09°while n-hexadecane SA ranged from 4.10°to 8.19°and n-hexadecane CAH ranged from 5.87°to 9.78°,showing dynamically hydrophobic-oleophobic property.The storage stability and chemical stability as well as the self-cleaning performance of SLPGS toward common liquid and solid contaminants in daily life were investigated.In addition,the possible mechanism of dynamical hydrophobicity-oleophobicity of SLPGS was preliminarily discussed.