Summary
Electronics that interface directly with the human body or with robots benefit from being flexible, lightweight, rugged and self-powered. Piezoelectric materials that can bend and stretch are well suited to pressure and force sensors and to mechanical energy harvesters. Here the authors introduce a large-area, flexible piezoelectric material made from sheets of electrospun fibres of the copolymer poly(vinylidene fluoride-co-trifluoroethylene), P(VDF-TrFE). By electrospinning the fibres into highly aligned arrays and poling them during fabrication, they obtain a high content of the electroactive β-phase and a strong, directional piezoelectric response. The resulting devices operate as sensitive conformal sensors and energy harvesters, demonstrated in applications from accelerometers to systems that scavenge mechanical energy for self-powered operation.