This story is a supplement to the feature "Self-Cleaning Materials: Lotus Leaf-Inspired Nanotechnology" which was printed in the August 2008 issue of Scientific American.
Massachusetts Institute of Technology researchers have developed multilayered superhydrophilic coatings that are antifogging and antireflective.
Alternating layers of polymer and nanoparticles of silica (which have hydroxyl groups bound to their surface) form a superhydrophilic coating that can be applied to glass and other materials. The coating surface is rough at the nanoscale, but the hydroxyl is strongly hydrophilic, which helps nanoscopic pores throughout the multilayers to soak up water like a sponge, instantly wicking it away from the surface.
A glass slide treated with these multilayers remains clear even when it is chilled in a fridge and then put in warm, humid air (left)—conditions that thoroughly cloud untreated glass (right).