Fabrication of Robust, Transparent, and Superhydrophobic Films on Glasses by a Sol-Gel Process

People gradually attach great importance to the application of the self-cleaning surface due to the environmental protection. The current experimental results show the stability of the films is still not robust enough to widely use. Therefore, for practical applications, the main study direction is to strengthen the hierarchical structure.
In this thesis, the hierarchical structure is fabricated with silica nanoparticles and TEOS at the solidifying temperature of 150℃ by sol-gel dip coating. Following to coat the PFOTS layer on the hierarchical structure and the superhydrophobic film is obtained. After the surface properties measurements, the effects of the withdrawing speed and the TEOS content are discussed.
The results show that the hydrophobicity, oleophobicity, and transmittance reduce with raising the withdrawing speed. The surface loses superhydrophobicity as the withdrawing speed exceeds 22.82 cm/min. Further, at the condition of the lower withdrawing speed (below 16.3 cm/min), the hydrophobicity, oleophobicity, and transmittance enhance with raising the ethanol dilute ratio. This effect cannot be observed when the withdrawing speed is higher than 22.82 cm/min. After the stability test, the best experimental parameters of the dilute ratio of 200 and the withdrawing speed of 16.3 cm/min can be found. At this condition, the water static contact angle of the surface is 167°; the contact angle hysteresis is 4°; the oil static contact angle is 140°; the transmittance is 91%.
To sum up, the robust, transparent, and superhydrophobic film can be fabricated at the low working temperature. This can promote the practical applications due to the less energy consumption and the low cost.