Mechanical Behavior of Blisters Spontaneously Formed by Multilayer 2D Materials

Abstract

Abstract Blisters can form spontaneously when transferring 2D materials on a substrate because of the small molecules trapped at the interface. Though extensive works have revealed a characteristic aspect ratio of these blisters by neglecting the bending effect of the layer, how the bending comes into play as the layer number increases has not been fully understood. Here, by simply measuring the profiles of blisters formed by transferred multilayer graphene and MoS 2 sheets, the variable profiles of blisters and the transition of their characteristic shape from a constant aspect ratio to a constant dome curvature are observed. Taking variable profiles of blisters and different characteristics of the interface into consideration, a theoretical model is established, and the mechanism of such transition is further analytically unveiled. In addition, based on this theory, the bending stiffness of sheets and the adhesion energy between sheets and substrates can be obtained simultaneously. This method is simple but robust, providing a new experimental way to explore the mechanical behavior of 2D material structures.