Scientists Design Versatile Self-Assembling Nanogears
For years, creating the gears and sprockets needed to make a microscopic robot has required the expensive and time-consuming process of silicon etching. Carving out each individual piece with a laser has made producing more than a couple of pieces prohibitively difficult and costly. A team at Columbia University now seems to have found a way around that problem. By laying a thin sheet of metal over a special layer of polymer, the team has created nanogears that assemble themselves, opening the possibility of much faster, cheaper, widespread production. To make the gears, a thin copper sheet is laid over a heat-expanded polymer. When the polymer cools, it shrinks faster than the metal, which causes the metal to bend. When the metal bends, it creates regularly spaced teeth in the polymer, effectively making a microscopic gear. Stiffer metal that's harder to bend creates a gear...