Gradient scaling phenomenon of piezoelectricity in non-piezoelectric polyvinylidene fluoride films

It has been well known that flexoelectricity can be exploited to generate an analogous piezoelectric response in non-piezoelectric materials. For the direct flexoelectric effect, the induced electric polarization is linearly proportional to the applied strain gradient. Therefore, it is logical to expect that such a piezoelectric response would be enhanced in the materials with reduced dimensions. In this paper, we will report our experimental observation of such a gradient scaling phenomenon of piezoelectricity in non-piezoelectric polyvinylidene fluoride (PVDF) films.