ORNL super water repellent could cause big wave...( OAK RIDGE Tenn. Nov. 29 2007 -- A wa...)

OAK RIDGE, Tenn., Nov. 29, 2007 -- A water repellent developed by researchers at the Department of Energys Oak Ridge National Laboratory outperforms nature at its best and could open a floodgate of commercial possibilities.

The super-water repellent (superhydrophobic) material, developed by John Simpson, is easy to fabricate and uses inexpensive base materials. The patent-pending process could lead to the creation of a new class of water repellant products, including windshields, eyewear, clothing, building materials, road surfaces, ship hulls and self-cleaning coatings. The list of likely applications is virtually endless.

My goal was to make the best possible water repellent surface, Simpson said. What I developed is a glass powder coating material with remarkable properties that cause water-based solutions to bounce off virtually any coated surface.

The ORNL nano-structured material maintains a microscopic layer of air on surfaces even when submerged in water, resulting in a profound change in the basic water-solid interface. Simpson likes to refer to this as the Moses effect.

Traditionally, Simpson noted that superhydrophobic coatings were expensive, were of poor water repellent quality or lacked the durability to make them practical.

Existing high-quality superhydrophobic materials are generally relegated to university research laboratories because they are difficult and expensive to produce, not scalable to large volumes and not amenable to being made into a commercially viable coating, Simpson said.

The process for making superhydrophobic glass powder is based on differentially etching of two glass phases from phase-separated glass. Simpson starts with borosilicate phase separating glass as the base material, which he heats to separate further. He then crushes this material into a powder and differentially etches the powder to completely remove the interconnected borate glass phase. Differential etchi
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