Preparation and Durability of Micron-Nano Synergistic Concrete-Structured Superhydrophobic Coatings

To uncover the intrinsic correlation between microscale morphology and durability of superhydrophobic coatings, three polytetrafluoroethylene (PTFE)-based superhydrophobic coatings with differentiated micro-nano structures were fabricated in this work. Sandpaper abrasion tests and environmental aging experiments were conducted, with water contact angle as the core evaluation indicator. Combined with microscopic morphology observation and surface roughness characterization, the durability of various coatings was systematically compared. The results show that the TiC/SiO2/PTFE micro-nano composite coating with a concrete-like structure possesses the optimal comprehensive durability. Nano-SiO2 constructs the rough superhydrophobic interface, micron TiC forms a rigid supporting skeleton to improve wear resistance, and the PTFE binder strengthens interfacial bonding. After reciprocating abrasion over 280 cm under a 123 g load, the water contact angle of this coating is still higher than 150°. Moreover, mild abrasion under low loads can slightly increase the static contact angle. After 210 days of outdoor exposure, the contact angle only decreases by 6.2°, and no obvious degradation of wetting performance is observed after 168 h of ultraviolet (UV) irradiation, demonstrating outstanding abrasion resistance and weathering stability. This work offers both theoretical guidance and experimental data for the structural design of long-term weather-resistant superhydrophobic protective coatings.