Non-uniform deformation of the dielectric subjected to external forces can induce the flexoelectric effect, a phenomenon that couples electrical polarization to strain gradients. However, limited by the size effects, flexoelectricity is not significant at the macroscale and only becomes catchable at the microscale and nanoscale. In recent work, we obtained a considerable flexoelectric-like response by crumpling the dielectric embedded with charges, i.e., the electret, which significantly improved the flexoelectric effect at the macroscale. In this work, we further optimize the macroscopic performance of the flexoelectric response by applying gradient treatment to the electret films. Specifically, we analytically derive the electromechanical coupling of crumpled electret films with gradients of different thicknesses, charge densities, and Young’s moduli as key design variables. It is shown that the gradient-oriented electret film can be tuned to nearly five times that of a uniform electret film.

电介质在外力作用下的不均匀变形会引起挠曲电效应，这是一种将电极化与应变梯度耦合的现象。然而，受尺寸效应的限制，柔性电在宏观尺度上并不显着，只有在微米尺度和纳米尺度上才变得可捕捉。在最近的工作中，我们通过压皱嵌入电荷的电介质（即驻极体）获得了相当大的类挠曲电响应，这在宏观尺度上显着改善了挠曲电效应。在这项工作中，我们通过对驻极体薄膜进行梯度处理，进一步优化了挠曲电响应的宏观性能。具体来说，我们分析推导了以不同厚度梯度、电荷密度和杨氏模量作为关键设计变量的皱褶驻极体薄膜的机电耦合。结果表明，梯度取向的驻极体薄膜可以调节到均匀驻极体薄膜的近五倍。