Preparation and performance of hydrophobic film based on SiO₂ with different particle sizes

The spherical SiO2 was used as raw material to prepare the first-level and second-level microstructure surface by layer-by-layer assembly method. The surface morphology, hydrophobic properties were characterized by SEM and contact angle measurement instrument and then the effect of the low surface energy modifications, different size, different level on the hydrophobic properties was studied, and the hydrophobic stability under different conditions were studied. The results show that the film is changed from hydrophilic to hydrophobic after modification; before modification, hydrophobic performance of second-level microstructure with the mixture of 2 μm and 20 nm SiO2 is higher than 2 μm or 20 nm microstructure in the first level and it is the same after modification, whose contact angle and rolling angle of second-level microstructure is 161.3° and 3.2°, respectively. The second-level microstructure surface can still maintain good hydrophobic performance after experiencing 240℃ high temperature and 200 h ultraviolet irradiation.