NewScientist reports scientists have developed a new ultrathin coating for LCD and plasma flat-screens, based on the rings left behind by spilled coffee.
Ivan Vakarelski at the Institute of Chemical and Engineering Sciences in Singapore realised that coffee stains could point the way to a cheaper alternative. Spill coffee and the evaporating liquid drives coffee particles to the edges of the spill - which ultimately produces the circular stain. The coffee granules are being "assembled" by the varying evaporation and convection rates in the fluid. Vakarelski and his colleagues figured that if they could mimic the process in a controlled fashion, they could create a pattern of granules of other materials to form a nanoscale conductive coating.
Instead of coffee, they started with a suspension of gold particles, each about 20 nanometres across. The suspension was left to dry on a glass plate covered with closely packed latex microspheres, each about 50 to 100 micrometres in diameter.