Fabrication of superhydrophobic silica-based surfaces with high transmittance by using polypropylene and tetraeyhoxysilane precursors

Preparation of superhydrophobic silica-based surfaces via sol-gel process by adding polyethylene glycol (PEG) polymer into the precursor solution has been developed. Surface roughness of the films was obtained by removing the organic polymer at 500 degrees C and then the hydrophobic groups bonded onto the films were obtained by self-assembly modification with a monolayer. Characteristic properties of the as-prepared films were analyzed by contact angle measurements, scanning electron microscopy, atomic force microscopy, UV-vis scanning spectrophotometer, and X-ray photoelectron spectrophotometer. The experimental parameters were varied by the type of silane species, the R ratio, the hydrolysis time of the precursor solution, the molecular weight of PEG, the pH value of mixing solution, and the dif ferent reagents for modification. The results showed that optimum ratio of TEOS/H2O/ethanol in the sol-gel process for precursor solution was set to 1/10/4. The better contact angles of the films can be obtained by the acid catalyst reaction, especially the pH value of mixing solution was adjusted to 0. When the as-prepared rough films were modified with (tridecafluoro-1,1,2,2-tetrahydrooctyl) dimethylchlorosilane (TFCS), the contact angle of the film can be promoted to 150.4 degrees, and the transmittance of the films in the visible light region was greater than 94.5%. (c) 2007 Wiley Periodicals, Inc.