Liquid-Repellent Surfaces Made of Any Materials

UCLA researchers in the Department of Mechanical and Aerospace Engineering have developed a structured surface that can be made of any material (but demonstrated with glass) that repels all liquids (even fluorinated solvents) without using any repellant coating.

Liquid-repellant surfaces have long been sough-after for a wide variety of applications ranging from consumer products and outdoor structures to chemical plants. However, such a variety of materials and needs make creating a surface that can work on all types liquids and environmental conditions very difficult. The existing methods of making surfaces liquid-repellant necessitate the material to be hydrophobic or require an application of a hydrophobic coating that will eventually wear off. While there have been efforts to create surface mimicking the liquid-repellant properties of the lotus leaf, none could remain repellent for long without the wax secretion mechanism of the living organism.

Professor C.J. Kim has devised a surface structure that repels all liquids, including aqueous solutions, organic and fluorinated solvents, that does not require the material to be hydrophobic or for a hydrophobic coating to be applied. This pattern functions regardless of what the solid surfaces are made from. This includes ceramics, metals and polymers. These surfaces are suited for a myriad of applications as a non-degradable or heat-resistant nonwetting surface. For electronic thermal management systems that use refrigerants, they can provide nucleation spots for phase-change heat transfer. The surface can also be made with a gradient pattern for droplet collection, separation, and transportation.

These surface structures may be used in various material embodiments as: