Stretchable heterogeneous adhesion with high debonding resistance by large-scale bridging

Stretchable adhesion is crucial for the implementation of soft materials but the debonding resistance of current stretchable adhesives is low due to the limited volume of fracture process zone. Herein, we propose a strategy to achieve stretchable adhesion with high debonding resistance by invoking large-scale bridging through programming structural heterogeneities. We lay out stiff segments of high bending stiffness in a soft matrix such that the soft segments function as stretchable bridges to provide the overall stretchability and the stiff segments function as rigid islands to provoke the large-scale bridging mechanism. We verify the principle by fabricating heterogeneous adhesives using poly(butyl acrylate- co -isobornyl acrylate) as the soft segment and polymethyl methacrylate as the stiff segment. We optimize the debonding resistance by tunning the stiff segment length to the saturated size of the bridging zone and obtain an enhancement of 13 times compared to the all-soft adhesives. As a proof-of-concept, we demonstrate a stretchable light strip and a stretchable bandage for notch repair. Engineering structural heterogeneities provides an alternative means to design stretchable adhesion with high debonding resistance.