Liquid-impregnated porous polypropylene surfaces for liquid repellency

Polypropylene is a popular plastic material used in consumer packaging. It would be desirable if such plastic containers were liquid repellent and not so easily fouled by their contents. Superomniphobic surfaces typically work by keeping the fouling liquid in a metastable state, with trapped pockets of air between the substrate and the liquid. An alternative method with greater long-term stability utilizes liquid-impregnated surfaces, where the liquid being repelled slides over an immiscible liquid immobilized on a porous surface. Here, we report a method for creating porous polypropylene surfaces amenable to liquid-impregnation. A solvent–nonsolvent polypropylene solution was deposited at high temperature to achieve the necessary porosity. Such surfaces were further functionalized with fluorosilane and dipped in the lubricating liquid to result in a durable, liquid-repellent surface. It is believed these liquid-impregnated surfaces will be more industrially viable than previous examples due to the ease of fabrication and their durability. These surfaces were found to exhibit repellency towards water, oils, shampoo, and laundry detergent with extremely low tilt angles due to the smooth liquid–liquid contact between the lubricating liquid and the liquid being repelled.