New coating keeps glass fog-free

US researchers say a new water-repellent coating for glass that resists both fogging and frosting could keep glass clear under the harshest of conditions. Writing in the American Chemical Society's journal Nano, scientists at the Massachusetts Institute of Technology say the coating could have uses ranging from automobile windshields to camera lenses. Michael F. Rubner and Robert E. Cohen and colleagues said current anti-fogging coatings that absorb water can reduce light scattering and the resultant distortion caused by condensation, but under conditions of extreme cold they can frost and become foggy. Looking to create a better coating to withstand aggressive conditions, they have developed a new coating that rapidly absorbs water molecules that cannot freeze in the coating. The coating also has a water-repelling or hydrophobic effect on larger water droplets that keeps them from spreading extensively on the coating but rather remain as flattened droplets, they said.