A carbon nanotube-coated "smart yarn" that conducts electricity could be woven into soft fabrics that detect blood and monitor health, engineers at the University of Michigan have demonstrated.
"Currently, smart textiles are made primarily of metallic or optical fibers. They're fragile. They're not comfortable. Metal fibers also corrode. There are problems with washing such electronic textiles. We have found a much simpler way---an elegant way---by combining two fibers, one natural and one created by nanotechnology," said Nicholas Kotov, a professor in the departments of Chemical Engineering, Materials Science and Engineering and Biomedical Engineering.
Kotov and Bongsup Shim, a doctoral student in the Department of Chemical Engineering, are among the co-authors of a paper on this material currently published online in Nano Letters.
To make these "e-textiles," the researchers dipped 1.5-millimeter thick cotton yarn into a solution of carbon nanotubes in water and then into a solution of a special sticky polymer in ethanol. After being dipped just a few times into both solutions and dried, the yarn was able to conduct enough power from a battery to illuminate a light-emitting diode device.
"This turns out to be very easy to do," Kotov said. "After just a few repetitions of the process, this normal cotton becomes a conductive material because carbon nanotubes are conductive."
The only perceptible change to the yarn is that it turned black, due to the carbon. It remained pliable and soft.