Study On Preparation And Hydrophobic Performance Of Organic/SiO₂ Hybrid Film

Wettability is a basic property of a solid surface, which has broad applications in the fields of daily life, industry, and agriculture, and so on. Usually, the wettability of solid surfaces is governed by their surface geometrical structures and surface free energy. The cooperation of micro/nano scale hierarchical structures and lower the surfaces results in the hydrophobic surface. This research paper summarized the development and the bionic fabrication method of hydrophobic surface. In this study, sol-gel method was used to fabricate organosilicon/SiO2 hydrophobic surface and materials.The main contents are summarized as follows:1. Transparent silica/organic silicon hybrid sol were formed using a facile, inexpensive sol-gel method. The hybrid sol was prepared by using hexamethyldisilazane (HMDS) as a surface modifying agent and the source of base catalyst required for the hydrolysis of tetraethoxysilane (TEOS). Hydrophobic coatings formed on different substrates by dip-coating techniques conveniently. The resulting silica-based coatings have shown an optical transmission over the visible range up to 89% (in reference to 100% transmission defined by a plain glass substrate) and high thermal stability. The water contact angle of the film reached 157°. Hydrophobic coatings with excellent optical transmittance were also successfully formed on writing paper and aluminum foils.2. Aluminum hydroxide sol was prepared by sol-gel method using AICl3 as precursor. Aluminum hydroxide sol was mixed with hybrid silica sol to prepare Si/Al mixed sols. The effects of the amount of Si/Al ratio and the concentration of the mixed sols on the hydrophobicity of films were inspected. Written paper was coated with mixed sol by dip-coating method. Hydrophobic surfaces with a contact angle as high as 147°and a low sliding angle were obtained. The surface keeps its hydrophobicity after immersed in water for 5 min. The present mixed sol can be used to protect files from moisture.3. Using cheap water glass and Dodecafluoroheptyl-propyl-trimethoxysilane(G502) as materials, spindly hydrophobic silica was prepared by sol-precipitation method. G502 was hydrolyzed before mixing with water glass. Effects of the concentration of water glass and the amount of hydrolyzed G502 solution to the size of silica were studied. The size of spindly silica is different under different experimental conditions, but the length-width axis ratio is a constant. The activation coefficient of samples was test. The activation coefficient of samples increases with the increasing the dose of G502 hydrolyzed solution.