Slippery icephobic materials

Slippery liquid-infused solid surfaces present a radically different approach to creating ice-repellent materials. State-of-the-art superhydrophobic surfaces frequently fail under high humidity, as the textures become coated with condensation and frost. The molecularly smooth liquid interface of SLIPS provides a comprehensive, integrated approach to ice prevention: the defect-free surface 1) enables incipient condensation droplets to slide off before they can freeze, 2) minimizes sites for ice nucleation, 3) ensures that free-sliding droplets freeze only in isolated patches rather than packed sheets, 4) minimizes ice adhesion, allowing frozen droplets to slide off under a small gravitational force, and 5) sheds droplets just as they start to thaw. 

We have developed a technique for directly fabricating SLIPS on any metal surface, bringing SLIPS technology to refrigeration, aviation, marine vessels, wind turbines, wires, and many more metal-based applications. Aluminum (Al) in particular is widely used for cooling fins in heat exchangers and as a lightweight structural material, and we have demonstrated that SLIPS-coated Al surfaces not only suppress ice and frost accretion by efficiently removing condensed moisture even under high-humidity conditions, but also exhibit at least an order of magnitude lower ice adhesion than state-of-the-art anti-ice coatings. We are currently partnering with the refrigeration and aviation industries to develop new SLIPS-enabled, energy-efficient, and safe technologies.

Publications

Wilson PW, Lu W, Xu H, Kim P, Kreder MJ, Alvarenga J, Aizenberg J. Inhibition of Ice Nucleation by Slippery Liquid-Infused Porous Surfaces (SLIPS). Physical Chemistry Chemical Physics [Internet]. 2013;15 :581-585. Full TextAbstract
Ice repellent coatings have been studied and keenly sought after for many years, where any advances in the durability of such coatings will result in huge energy savings across many fields. Progress in creating anti-ice and anti-frost surfaces has been particularly rapid since the discovery and development of slippery, liquid infused porous surfaces (SLIPS). Here we use SLIPS-coated differential scanning calorimeter (DSC) pans to investigate the effects of the surface modification on the nucleation of supercooled water. This investigation is inherently different from previous studies which looked at the adhesion of ice to SLIPS surfaces, or the formation of ice under high humidity conditions. Given the stochastic nature of nucleation of ice from supercooled water, multiple runs on the same sample are needed to determine if a given surface coating has a real and statistically significant effect on the nucleation temperature. We have cycled supercooling to freezing and then thawing of deionized water in hydrophilic (untreated aluminum), hydrophobic, superhydrophobic, and SLIPS-treated DSC pans multiple times to determine the effects of surface treatment on the nucleation and subsequent growth of ice. We find that SLIPS coatings lower the nucleation temperature of supercooled water in contact with statistical significance and show no deterioration or change in the coating performance even after 150 freeze–thaw cycles.

Media Coverage

Super-Slick Material Keeps Ice From Forming, Technology Review, July 2, 2014. 

Ice-Phobic Surfaces that are Wet, ACS Nano, August 9, 2012. 

Ice Curbs, National Science Foundation's Discovery Files (podcast), June 27, 2012. 

'Ice-Phobic' Airplane Wings, Wall Street Journal, June 22, 2012. 

SEAS Team Develops Ice-Repelling Technology, The Harvard Crimson, June 18, 2012. 

No Scraper Required: Ice Rolls Off Metal, Discovery, June 16, 2012. 

Slippery Coating Keeps Metals Frost-Free, Chemical and Engineering News, June 15, 2012. 

Keeping Metal Surfaces Ice, Frost Free, The Hindu, June 14, 2012. 

Ultra-Antifreeze Keeps Ice From Even Forming, Smithsonian, June 12, 2012. 

A new spin on anti-freeze, Harvard press release, June 11, 2012.