Robust Flower-Like TiO2@Cotton Fabrics with Special Wettability for Effective Self-Cleaning and Versatile Oil/Water Separation

Inspired by the hierarchical structure of the mastoid on the micrometer and nanometer scale and the waxy crystals of the mastoid on natural lotus surfaces, a facile one-step hydrothermal strategy is developed to coat flower-like hierarchical TiO2 micro/nanoparticles onto cotton fabric substrates (TiO2@Cotton). Furthermore, robust superhydrophobic TiO2@Cotton surfaces are constructed by the combination of hierarchical structure creation and low surface energy material modification, which allows versatility for self-cleaning, laundering durability, and oil/water separation. Compared with hydrophobic cotton fabric, the TiO2@Cotton exhibits a superior antiwetting and self-cleaning property with a contact angle (CA) lager than 160 degrees and a sliding angle lower than 5 degrees. The superhydrophobic TiO2@Cotton shows excellent laundering durability against mechanical abrasion without an apparent reduction of the water contact angle. Moreover, the micro/nanoscale hierarchical structured cotton fabrics with special wettability are demonstrated to selectively collect oil from oil/water mixtures efficiently under various conditions (e.g., floating oil layer or underwater oil droplet or even oil/water mixtures). In addition, it is expected that this facile strategy can be widely used to construct multifunctional fabrics with excellent self-cleaning, laundering durability, and oil/water separation. The work would also be helpful to design and develop new underwater superoleophobic/superoleophilic materials and microfluidic management devices.