One-step hydrothermal fabrication of CuO/TiO 2 @SA superhydrophobic composite coating for efficient oil–water separation and anti-icing

Superhydrophobic materials show great potential for oil–water separation, self-cleaning and anti-icing, yet conventional fluorinated systems endanger both health and the environment, while poor durability and limited multifunctionality still block their real-world use. In this study, a one-step hydrothermal strategy was successfully employed to construct CuO/TiO2 composite nanoparticles with a smaller particle size, uniform distribution, and a unique "rice-grain-like" morphology. Through synergistic modification with stearic acid (SA), the resulting CuO/TiO2@SA composite coating exhibited a water contact angle (WCA) greater than 160° and outstanding durability under extreme conditions. This synergistic effect significantly enhanced the mechanical stability and durability of the coating, enabling it to maintain a WCA exceeding 150° after abrasion, kneading, tape-peeling, and ultrasonic treatment. Moreover, the CuO/TiO2@SA coating demonstrated excellent chemical stability during freeze-thaw cycles at -20°C, allowing rapid ice removal in low-temperature and high-humidity environments. Meanwhile, the composite coating achieved an oil-water separation efficiency of over 95% without performance degradation after ten cycles. This work transcends the conventional design philosophy of single-function coatings and integrates multiple functionalities, offering a new strategy and important insights into developing superhydrophobic coatings, oil-water separation materials, and anti-icing materials with high mechanical and chemical stability.