3-Dimensional Ink

Most people are familiar with three-dimension drawings, which are of course rendered on two-dimensional surfaces in a way that gives the illusion of depth. Jennifer Lewis (jalewis@ux1.cso.uiuc.edu, 217-244-4973) and colleagues at the University of Illinois, however, are developing techniques to draw truly 3-D structures. The researchers are perfecting "inks" that carry tiny particles made of metals, ceramics, plastics, or a variety of other materials instead of pigments. The inks are deposited with a machine similar to an ink jet printer.

But unlike most inks, the fluid that the printer deposits is a gel that can be built up, layer by layer, into three-dimensional structures. The gel must be thick enough to support itself as it spans empty space. (Imagine, for instance, squeezing out a stream of toothpaste across your fingers. The line of toothpaste can, at least for a little while, support itself across a small gap between two fingers.) It also must be designed to retain its shape without significant shrinking or sagging as it hardens. The manufacturing technique may soon lead to novel structures woven of inky threads only tens of microns in diameter (see image). Lewis will present recent studies of 3-D inks on October 14 at the 74th Annual Society of Rheology Meeting, in Minneapolis.