A Flexible Shape Memory Polymer Adhesive with Dual Adaptations

A shape memory polymer (SMP) makes conformal and hermetic contact with a target surface at its soft, rubbery state, while it produces a high-strength dry adhesion at the rigid, glassy state. Recent SMP adhesive investigations demonstrate that SMP can stick to a variety of rough surfaces as well as rigid surfaces underwater. However, it is somehow challenging to achieve and maintain a strong adhesion on a flexible adherends such as common fabrics due to a modulus mismatch where the flexible adherends would easily be peeled off from SMP adhesives which are too rigid to adapt to the target surface flexing. Here, we present the dual adaptation of an SMP adhesive consisting of a thin SMP layer and a backing fabric, which involves the shape adaptation to produce a strong adhesive contact and the flexure adaptation to tolerate a flexing target surface. In order to determine the criteria for optimizing both shape and flexure adaptations, we present a theoretical justification and computational and experimental research. On the basis of these results, we demonstrate a dry and underwater adhesion performance of a thin SMP adhesive on common clothing to highlight its potential applications.