Most people do not give surfaces a second thought, but for Varanasi they form the basis of everything. His days working at General Electric taught him how crucial a surface can be.
“One of the areas where I saw significant challenges was surfaces and interfaces,” Varanasi says. “Every phenomena happens on a surface or an interface. Whether it be energy transport or mass transport, everything happens at an interface between two materials.”
When Varanasi came to MIT, one of the first things he did was address the classic 100-year-old problem of moisture-induced efficiency losses in steam turbines. To solve it, Varanasi developed a completely new class of highly non-wetting, super-slippery, multi-structured liquid coatings that repel water droplets that impact or condense on the surface, thus preventing moisture from forming on blades. He says that the coating can be applied using the existing coating equipment by simply modifying the processes and materials, thus opening up retrofitting opportunities at every level of the value chain.
Conversely, Varanasi’s super-wetting coatings combat the opposite problem of surfaces so hot that vapor forms over them and repels any water, such as that used for cooling purposes. It’s precisely the situation that can cause such powerplant disasters as the one that occurred in Fukushima, Japan, in 2010. Varanasi and his group have developed new nano-engineered, multi-structured highly wetting coatings to solve this problem. At temperatures greater than 400 degrees Fahrenheit, he is able to get the water droplets to anchor to the surface. Some of his other areas of work include coatings that prevent ice build-up on aircrafts or power lines, novel separation membranes, coatings that prevent hydrate plugs in deep sea oil wells for improved flow assurance, enhancing water recovery in desalination, power generation, agriculture, and oil and gas, as well as developing new approaches for scalable manufacturing of these nano-engineered surfaces and coatings.
“Coating manufacturing requires integration and collocation of various disciplines and helps de-commoditization of technology. It opens up a large scope for retrofit opportunities that can allow for tracking advancing frontiers and lead to continuous transformation of products and thereby create local jobs. It can also lead to reduced dependence on imported and expensive materials,” Varanasi says.
Varanasi has received several awards in recent years, including the DARPA Young Faculty Award and the NSF CAREER Award. His newest surface coating invention, LiquiGlide, a nontoxic, nonstick, super slippery coating for condiment bottles, has received international attention recently, and was named a best invention of 2012 by Time magazine.