Professor John Rogers at the University of Illinois is working on a stretchable silicon that will pave the way for integrating electronics into surgical gloves, enabling them to monitor a range of biological parameters.
Researchers at the University of Illinois at Urbana-Champaign recently showed how silicon can stretch in one dimension, like a rubber band. (See “Stretchable Silicon.”) Now, in the group’s most recent work, the researchers have made sheets of silicon that can stretch in two dimensions as well, which could make it possible to put electronics on spheres and surfaces with complicated shapes.
The new results from the Illinois team, led by John Rogers, a professor of material science and engineering, build on the group’s earlier research with one-dimensional stretchy ribbons of silicon, in which they affixed ultrathin ribbons to a prestretched piece of rubber. When the strain on the rubber was released, the silicon ribbons buckled. Subsequently, the ribbons could be stretched again, pulling the silicon taut. However, these ribbons could only stretch in one dimension. A truly conformable sheet of electronics needs to stretch in two directions so it can, for instance, cover a sphere or some other three-dimensional object.
… The researchers affixed sheets of silicon–ranging in size from three to five square millimeters and in thickness from 55 to 320 nanometers–to a stretched-out sheet of rubber. When the stretch was released, the silicon buckled to form complicated waves and zigzags, creating a never-before-seen silicon geometry (see multimedia video). Rogers says that his team was surprised by the actual geometry, a herringbone pattern, which resembles the varying diagonals of the fish’s backbone. Essentially, the snaking patterns of waves allow the sheets of silicon to stretch to two dimensions.
This device design, Rogers says, could be used in a smart surgical glove that would measure the concentration of hormones or pH in the body, for instance. In addition, the team is building an array of photo detectors on the stretchy silicon and placing it around a sphere to create an electronic eye.