Mechanical Analysis and Experimental Studies of the Transverse Strain in Wrinkled Metallic Thin Films

Abstract

The wrinkling structures, which can greatly improve the stretchability of the metallic thin films, have been widely used in the preparation of stretchable devices. However, the artificial wrinkling structures are often accompanied by the generation of microcracks, which seriously affect the performance of the devices. In this work, by establishing the corresponding model, the transverse strain of the longitudinally prestrained continuous film and the strip film is mechanically analyzed, which is verified by experimental results; for the strain of blank substrate, the error of the model was about 3.7%. It is difficult to avoid the generation of microcracks with continuous films, but strip films can avoid the generation of microcracks to a certain extent. The experimental results illustrate the various factors affecting the generation of microcracks. The transverse strain of the film is proportional to the substrate’s Young’s modulus, Poisson’s ratio, thickness, and prestrain and is basically inversely proportional to the strip film’s Young’s modulus, thickness, and strip interval. Our results provide deeper knowledge for choosing proper metallic materials to fabricate stretchable wrinkled devices.