Piezoelectric microstructured fibers via drawing of multimaterial preforms

Abstract

We demonstrate planar laminated piezoelectric generators and piezoelectric microstructured fibers based on BaTiO 3 -polyvinylidene and carbon-loaded-polyethylene materials combinations. The laminated piezoelectric generators were assembled by sandwiching the electrospun BaTiO 3 -polyvinylidene mat between two carbon-loaded-polyethylene films. The piezoelectric microstructured fiber was fabricated via drawing of the multilayer fiber preform, and features a swissroll geometry that have ~10 alternating piezoelectric and conductive layers. Both piezoelectric generators have excellent mechanical durability, and could retain their piezoelectric performance after 3 day's cyclic bend-release tests. Compared to the laminated generators, the piezoelectric fibers are advantageous as they could be directly woven into large-area commercial fabrics. Potential applications of the proposed piezoelectric fibers include micro-power-generation and remote sensing in wearable, automotive and aerospace industries.Driven by the ever-growing market of the personal wearable products such as on-garment displays, health-monitoring sensors 1 , virtual-reality devices, smart watches and bracelets, and intelligent glasses, extensive effort has been devoted to the R&D of soft and wearable electronics 2 . The development of wearable and portable electronics has inspired much work 3 in the design and fabrication of flexible fibers which could be used as power sources or sensor components. Among all of these fiber generators or sensors, piezoelectric fibers that operate based on piezoelectric effect 4, 5 are especially attractive, because they could convert mechanical vibrations accessible in our daily life (i.e. walking 6 , air flow 7 and heart beating 3, 8 ) into electrical signals. Another application of piezoelectric generators is related to automotive or aerospace industries 9, 10 . Piezoelectric generators or sensors are implanted on the airplanes and vehicles, for the purpose of structural integrity monitoring 11 , as well as powering the on-board electronic systems such as wireless sensor networks (WSNs) with low-power consumption 12 18 . However, for these fibers, frequent and intensive mechanical movements may potentially damage the fiber structure (e.g. the continuous bending can make the piezoelectric layers cracking, and even peeling off from the fiber core). Thus, the as-fabricated fiber generators typically suffer from poor mechanical reliability, which makes them unsuitable for truly wearable applications. To improve robustness of the fibers, Zhang et al. have coated a thin layer of polydimenthylsiloxane (PDMS) on the roots of ZnO NWs using surface-coating combined with plasma-etching16 . An alternative route for fabrication of the piezoelectric fibers involves the utilization of piezoelectric polymers. In principle, piezoelectric fibers based on piezoelectric polymers usually feature better mechanical robustness and flexibility 19 . Among all of these piezoelectric polymers, poly(vinylidene fluoride) (PVDF) and poly(vinylidene f...