New way of keeping metal surfaces ice, frost-free

June 12th, 2012 - 5:38 pm ICT by IANS  

Washington, June 12 (IANS) Harvard researchers have invented a way to keep any metal surface free of ice and frost - a discovery that will prove beneficial in refrigeration systems, wind turbines and the construction industry.

The surfaces treated with the chemical quickly shed even tiny, condensation droplets or frost.

The technology prevents ice sheets from developing on surfaces - and any ice that does form, slides off effortlessly. The discovery has direct bearing on a wide variety of metal surfaces such as those used in refrigeration systems, wind turbines, aircraft, marine vessels, and the construction industry.

The group, led by Joanna Aizenberg, professor of materials science at the Harvard School of Engineering and Applied Sciences (SEAS), previously introduced the idea that it was possible to create a surface that completely prevented ice with ice-repellent coatings, inspired by the water repellent lotus leaf, the journal ACS Nano reports.

Yet this technique can fail under high humidity as the surface textures become coated with condensation and frost. To combat this problem, researchers recently invented a radically different technology that is suited for both high humidity and extreme pressure, called SLIPS (Slippery Liquid Infused Porous Surfaces).

“Unlike lotus leaf-inspired icephobic surfaces, which fail under high humidity conditions, SLIPS-based icephobic (non-stick) materials, as our results suggest, can completely prevent ice formation at temperatures slightly below zero degree Celsius while dramatically reducing ice accumulation and adhesion under deep freezing, frost-forming conditions,” said Aizenberg.

The challenge was to apply this technology to metal surfaces, especially as these materials are ubiquitous in our modern world, from airplane wings to railings, according to a Harvard statement.

Aizenberg and her team developed a way to coat the metal with a rough material that the lubricant can adhere to. The coating can be finely sculpted to lock in the lubricant and can be applied over a large scale, on arbitrarily shaped metal surfaces. In addition, the coating is non-toxic and anti-corrosive.

Researchers successfully applied the technology to refrigerator cooling fins and tested it under a prolonged, deep freeze condition. Compared to existing “frost-free” cooling systems, their innovation completely prevented frost far more efficiently and for a longer time.

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