Piezoelectric Fibers Form Fantastic Fabric

An optical fiber with a piezoelectric component that can be woven into a fabric suggests applications with a sci-fi quality—clothing that acts as a microphone, meshes of sensors that monitor oceanic currents, or sensors that monitor blood flow inside tiny capillaries. Yoel Fink of Massachusetts Institute of Technology and colleagues have designed such fibers that not only transmit optical signals but vibrate in response to an electric current, or, vice versa, produce electric current in response to mechanical forces (Nat. Mater., DOI: 10.1038/nmat2792). The piezoelectric effect stems from uniformly asymmetrical charge densities, a condition that’s been difficult to achieve in the disordered glassy materials traditionally used in optical fibers. Fink’s group prepared fibers that are tens of meters long and are covered in a sheath of the piezoelectric copolymer poly(vinylidene-fluoride-trifluoroethylene). In one application scenario, the researchers envision that an optical signal can be altered by electrical signals that mechanically squeeze the piezoelectric coating.