Strain gradient induced electric polarization in alpha-phase   polyvinylidene fluoride films under bending conditions
  The relationship between the applied elastic strain gradient and the induced electric polarization in the alpha-phase polyvinylidene fluoride (PVDF) films under bending conditions has been investigated. Our experimental studies have shown that the flexoelectric polarization is linearly proportional to the strain gradient and the corresponding direct flexoelectric response is strong. It is reasonable to believe that the physical mechanisms behind the flexoelectric effects in polymers and solid dielectrics are different. 
Sivapalan Baskaran, Xiangtong He, Yu Wang, John Y. Fu
cond-mat.mtrl-sci