Ricerc@Sapienza

In the last years flexible, low-cost, wearable and innovative piezoelectric nanogenerators (NGs), i.e. devices able to convert the mechanical energy into electrical energy at micro- and nano-scale, have attracted a considerable interest to develop energy harvesters and sensors. Among the piezoelectric materials of particular interest are: a) the zinc oxide (ZnO) nanostructures, such as nanorods or nanowalls; b) the Poly(vinylidene fluoride) [PVDF] and its copolymer Poly(vinylidene fluoride-co-trifluoroethylene) [PVDF-TrFE], which are among the most interesting piezoelectric polymers. Recent literature reports how combining the piezoelectric properties of the ZnO nanorods (NRs) and thin film of PVDF make this hybrid nanostructure particularly promising for the production of flexible piezoelectric NGs. The aim of this research project is to develop and characterize flexible NGs for wearable applications, based on PVDF polymer matrix, suitably synthesized and embedding ZnO NRs grown by means of a Chemical Bath Deposition (CBD) (already developed and patented by the research group). In addition, to improve the piezoelectric response of the hybrid nanostructure we propose to fill the PVDF/PVDF-TrFE with ferromagnetic nanoparticles (NP), such as ferrites, and to exploit a magnetic poling. The combination of the hybrid structure ZnO NRs and suitably synthesized PVDF/PVDF-TrFE films with the ferromagnetic NP and magnetic poling will allow to obtain novel flexible and high performance NGs. The fundamental aspects that will be studied and investigated in depth are related to the optimization of the PVDF/ferromagnetic NP nanocomposite, proper choice of ferromagnetic NPs and control of the magnetic poling process.