Mechanisms for Enhancing Polarization Orientation and Piezoelectric Parameters of PVDF Nanofibers

Many emerging applications strongly demand flexible and efficient electromechanical conversion materials. Polymeric piezoelectric materials, with ability of large area and low temperature processing, are attractive to obtain wide applications for electromechanical sensors, transducers, and mechanical energy harvesters. A major drawback of the polymeric piezoelectric materials is their much lower piezoelectric performance property, such as piezoelectric strain coefficient, than their ceramic counterparts. Here, outstanding piezoelectric performance properties with giant effective strain and voltage coefficients of - 116 pm V-1 and - 1180 V mm N-1 are achieved in electrospun polyvinylidene fluoride nanofiber films from the precursor solution modified with hydrated salt. The experimental results and theoretical analysis clarify a synergistic interactive role from the hydrated salt and the electric field during electrospinning, effectively leading to polarization enhancement and alignment, and hence the giant macroscopic piezoelectric coefficients in the obtained electrospun fiber films. The demonstrated results and the understanding on the underlying mechanism exhibit the potential and strategy in achieving high-performance functional materials through dedicated control on their nanostructures and polarizations.