No abstract

Traditionally. slippery lubricant infused surfaces, inspired by Nepenthes, suffer from low durability, owing to the migrating, evaporating, and leaking of the infused lubricants. Herein, to address this challenge, a lubricant-impregnated coating with long-term stable slipperiness and self-replenishment properties is presented. By simple immersion in silicone oil, substrates coving with PDMS coating gain a slippery, long-lasting lubricated surface. The slippery coating repels water and corrosive liquids, resists ice and ketchup adhesion, and exhibits enhanced optical transparency. The resulting coating maintains its water repellency and slipperiness after mechanical bending, water jetting, tissue wiping, and knife scratching. The obtained slippery coating also repels hot liquids such as boiling water, and it also can be tolerant to thermal treatment at 125 °C for 1 d. More importantly, the slippery coating can self-lubricate upon lubricated liquid overlayer depletion through simple diffusion of the lubricant from the oil absorbed in the cross-linked PDMS network.

No abstract

Hydrophilic materials are easily fouled by organic contaminants owing to their high surface energy, and this oil-fouling problem severely hinders their use in practical applications. To address this challenge, herein, a hydrophilic coating with oil repellency and photocatalytic activity is developed by a spray-casting process. In the air surrounding, a water droplet spreads over the coating surface completely, while oil droplets exhibit contact angles more than 150°and moving on the coating freely. The water-wetted coating still had oil repellency, as the water layer on the coating surface can act as a lubricant to repel oil. Although methylene blue aqueous solution contaminates the coating by wetting it completely, these water-soluble organic molecules can be removed by UV illumination, due to the photocatalytic activity of the coating. Exploiting its water-attracting and oil-repelling properties, the coating deposited on a copper mesh is applied as a multiplatform for oil−water separation with high separation efficiency. This study provides a novel and efficient way to solve the oil-fouling problem of hydrophilic materials.

Development of a robust self-cleaning oil-repellent surface in a cost-efficient and green manner is highly desirable, yet still difficult to realize. Herein, we develop a poly­(vinyl alcohol) (denoted as PVA) composite hydrogel on which the oily contaminations can be removed efficiently by water merely. Owing to its high affinity to water and resistance to oils, the water-wetted hydrogel establishes a slippery oil-repellent state in air, displays underwater superoleophobicity with ultralow adhesion to all probe oils, and blocks oil from permeating when immersed into an oil surrounding. Oily contaminations on the PVA hydrogel surface are removed just by titling or water immersion, with no oil residue left behind. This enhanced oil repellency was retained after hand-bending, water-jetting, and even 1000 cycles of sand abrasion, demonstrating mechanical robustness. Application of the PVA hydrogel-coated copper mesh is demonstrated to separate oil/water and oil/oil mixtures, with separation efficiency being greater than 98%.