Micro–nano hierarchical structured SiO2-based hydrophobic films with long-term self-cleaning and anti-graffiti properties on high-speed EMUs

During the operation of high-speed EMUs, a large number of pollutants accumulate on the paint surface due to collisions with birds and insects, resulting in a decrease in the cleanliness of the vehicle body. Although cleaning can improve the condition, it also causes scratches and damage to the surface of the vehicle paint, ultimately seriously affecting the aesthetics of high-speed EMUs. Spraying self-cleaning hydrophobic materials can greatly reduce the cost and time of cleaning the vehicle body. This work synthesized a self-cleaning hydrophobic material using micro–nano hierarchical structured SiO₂ as an additive, and sprayed it onto the surface of the opening and closing cover of high-speed EMUs. The self-cleaning hydrophobic film formed exhibited excellent long-term weather resistance performance. The results show that after 12 months of operation (with a mileage of 56.9 km), the internal structure of the hydrophobic film of the high-speed EMUs is basically stable. After 24 months of operation (with a mileage of 1.137 million km), the water contact angle of the self-cleaning hydrophobic film can still reach 94.4°, the glossiness remains at 93.9 GU, and it has excellent anti-graffiti performance and droplet sliding performance.

Graphical Abstract