Keeping the Ice OffCategory: Science & Technology
Posted: June 12, 2012 05:27AM
We have two freezers at my house; one built into a refrigerator and the other is actually a chest freezer. Every so often we have to clean out the ice that has built up inside of them to get back some room in the freezers and to make sure they seal properly. Researchers at Harvard University have developed a technology which will prevent ice and frost from building up on metal. Not only could this help with household freezers, but also airplanes, wind turbines, and anything else that is exposed to low temperatures at water vapor.
In the past researchers have tried to develop hydrophobic surfaces that would simply prevent water from collecting on the surface, to prevent it from freezing. Unfortunately at high humidity this method does not work and the surface will still ice-over. Taking a new approach, the Harvard researchers developed Slippery Liquid Infused Porous Surfaces (SLIPS) which hold a molecularly flat liquid surface behind a nanostructure surface. Essentially, SLIPS makes the surface defect free because the trapped liquid is perfectly smooth, so any slippery material just slides off.
At temperatures above 0º C, SLIPS works to prevent any ice from forming on the surface. If the temperature drops below the freezing point though, ice can still form on the surface, but is much easier to get off. In fact, in the case of an airplane and wind turbine, the normal motions of and forces on the surfaces could cause any ice that does form to just slide off, making it ice-proof.