A polymer coating that transforms opaque water droplets into smooth transparent sheets could be used to keep glass from fogging. "You can never stop water from condensing on a surface. But if you can create a surface where the water spreads out & forms a thin film, it's perfect for anti-fogging," says Michael Rubner, of MA Institute of Technology, US, whose team has developed the new coating. "The water's still there, but you can't see it." Fog is caused when steam condenses on a cool surface & forms minuscule water droplets due to the water's surface tension. Water molecules are more attracted to each other than to air molecules & form a spherical shape to maximise contact between water molecules, leaving as few as possible exposed to air. But water is also attracted to glass, & if this attraction is enhanced, it can overcome the surface tension.
