Effect of flexoelectricity on buckle-delamination of nanofilms adhered to compliant substrates

Abstract

Buckle-delamination, a typical instability mode, can spontaneously introduce large, sizable-area and tunable strain gradients in nanofilms adhered to compliant substrates, which helps to exploit the flexoelectric effect. However, the role of flexoelectricity in the buckle-delamination behavior of dielectric nanofilms remains unclear. Here, an electromechanical coupling model is developed to capture the flexoelectric effect in buckle-delaminated films on compliant substrates. The energy analysis indicates that the interplay between flexoelectricity and buckling promotes the delamination process by increasing the width of buckle-delaminated blisters. Moreover, the coupling of flexoelectricity and piezoelectricity breaks the anti-symmetric distribution of in-plane stress, thereby affecting the position and magnitude of the maximum tensile stress. We also investigate the size-dependent effect of flexoelectricity in buckle-delamination behavior and demonstrate its crucial role in films of nanoscale thickness. This work can advance the understanding of the flexoelectric effect in buckle-delamination behavior and pave the way for its practical applications.