The flexibility in recently developed freestanding oxide films makes them fertile for exploring buckling-based flexible electronic devices at nanoscale. However, the rigorous flexoelectric theoretical model has not been established for accurately describing the buckling in a delamination film-substrate system yet. In this paper, we establish an electromechanical model by taking flexoelectricity into account to investigate the buckling properties of freestanding films. The results demonstrate the strain gradient of up to 10⁶ m⁻¹ in buckling films induces a giant flexoelectric effect. The flexoelectricity significantly suppresses the buckling deformation, of which the critical strain increases nearly tenfold as well as the buckling amplitude reduces by half. Meanwhile, flexoelectricity drives a size-dependent buckling behavior that differs from classical elastic buckling, in which the films with a smaller size exhibit a larger buckling resistance. These theoretical findings are well-confirmed experimentally. This work highlights the critical role of flexoelectricity in buckling films at nanoscale and provides guidelines for the design of buckling film-based flexoelectric devices.

最近开发的独立式氧化膜的灵活性使其非常适合探索纳米级基于屈曲的柔性电子器件。然而，尚未建立严格的挠曲电理论模型来准确描述分层薄膜-基底系统中的屈曲。在本文中，我们建立了考虑挠曲电的机电模型，以研究独立式薄膜的屈曲特性。结果表明应变梯度高达 10 ⁶ m ^-1屈曲薄膜中会产生巨大的挠曲电效应。挠曲电显着抑制了屈曲变形，其临界应变增加了近十倍，屈曲幅度减少了一半。同时，挠曲电驱动了与尺寸相关的屈曲行为，这与经典的弹性屈曲不同，在经典的弹性屈曲中，尺寸较小的薄膜表现出较大的屈曲阻力。这些理论发现得到了实验的充分证实。这项工作强调了挠曲电在纳米级屈曲薄膜中的关键作用，并为基于屈曲薄膜的挠曲电器件的设计提供了指导。