Wow, piezoelectric fibers are being developed by MIT! From ScienceDaily:

For centuries, “man-made fibers” meant the raw stuff of clothes and ropes; in the information age, it’s come to mean the filaments of glass that carry data in communications networks. But to Yoel Fink, an Associate professor of Materials Science and principal investigator at MIT’s Research Lab of Electronics, the threads used in textiles and even optical fibers are much too passive. For the past decade, his lab has been working to develop fibers with ever more sophisticated properties, to enable fabrics that can interact with their environment.

Ordinary optical fibers are made from a “preform,” a large cylinder of a single material that is heated up, drawn out, and then cooled. The fibers developed in Fink’s lab, by contrast, derive their functionality from the elaborate geometrical arrangement of several different materials, which must survive the heating and drawing process intact.

The heart of the new acoustic fibers is a plastic commonly used in microphones. By playing with the plastic’s fluorine content, the researchers were able to ensure that its molecules remain lopsided — with fluorine atoms lined up on one side and hydrogen atoms on the other — even during heating and drawing. The asymmetry of the molecules is what makes the plastic “piezoelectric,” meaning that it changes shape when an electric field is applied to it.