Preparation and Characterization of Transparent Hydrophobic Al2O3 Surface by Vacuum Cold Spray

Transparent hydrophobic materials have broad application prospects in industry and daily life due to its transparent and super-hydrophobic characteristics. However, hydrophobicity and transparency are competitive properties from the viewpoint of surface roughness. A novel and simple method to fabricate transparent hydrophobic surface is introduced in the present paper. Micron and sub-micron-sized Al₂O₃ powders mixture was used to deposit Al2O3 coating on the plastic substrates by vacuum cold spray. The coatings were modified by heptadecafluorodecyl trimethoxysilane (FAS) to reduce the surface energy. The surface morphology was characterized by scanning electron microscopy (SEM) and 3D laser microscopy (LSM). The transmittance of the coatings was also investigated. The results show that the as-sprayed coatings exhibit a rough surface of sub-micrometer structure. After FAS absorbing treatment, the deposited Al₂O₃ coating present hydrophobic characteristic, and the transmittance of Al₂O₃ coatings on plastic substrates are close to 90% in the range of visible light.