Stronger flexoelectricity from the laminated film subjected to crumpling deformation

Non-uniform deformation of the dielectric subjected to external forces can induce the electrical response, i.e., flexoelectricity. The crumpling of a thin dielectric film can induce considerable strain gradients (i.e., non-uniform deformation), and due to flexoelectricity, considerable polarization occurs. In this paper, to improve the flexoelectric response when the dielectric film undergoes crumpling deformation, we investigate the crumpling problem of the three-layer laminated film whose edge layers have the same thickness. A theoretical model for the crumpling problem of the laminated film is developed. The induced flexoelectric effect associated with it is analyzed. The results indicate that the laminated films with reduced Young’s modulus in the edge layers can effectively improve the flexoelectric response of the film subjected to crumpling deformation. The optimal size of the laminated film appears around three times of magnitude higher than that of the homogeneous film. At the same time, the flexoelectric energy efficiency of the laminated film is one order higher than that of the homogeneous film. Therefore, the laminated film is more justifiable on practical application. This work can provide a theoretical basis for the design of miniature energy-capture devices with high energy conversion efficiency.