Abstract：Large-area and tunable strain gradients has been shown to be introduced by the inhomogeneous deformation in the wrinkled thin film. The great potential of the wrinkled thin film in the application field of the flexoelectric effect has attracted wide attention. The structure and buckling mode of wrinkled thin films have become the focus of attention. In this paper, an electromechanical coupling model is developed to study the buckling behavior of thin-film and finite thickness substrate structures with flexoelectric effect. Firstly, the influence of flexoelectric effect on the buckling evolution of the thin-film substrate structure is studied by the minimum energy method. Then, two kinds of buckling modes global buckling and local wrinkling are distinguished by changing the structural parameters and flexoelectric coefficient. The results show that the stronger the flexoelectric effect in the film, the more slender the film structure, and the more likely global buckling occurs. The stronger the flexoelectric effect in thin films, the larger the critical strain required for buckling, and the more prominent the influence on the local wrinkling mode. The larger the amplitude of the local wrinkling mode, the smaller the maximum strain in thin films. For the local wrinkling mode, the wrinkle is more sparse and the wrinkle amplitude is larger when the flexoelectric effect is stronger. When the flexoelectric effect is increased to a certain extent, the buckling mode of the thin film changes from local wrinkling mode to global buckling mode. The existence of flexoelectric effect will increase the stiffness of the structure and improve the stretchability of the structure. It is also found that the flexoelectric polarization can be adjusted continuously by compressive strain, and the controllability of flexoelectric effect in wrinkled thin films is important for the generation and control of material polarity. These findings will contribute to the design and application of electromechanical devices on micro and nano scale.
2025, Vol. 46 
