Patterns, forces, and metastable pathways in debonding of elastic films

Abstract

This Letter resolves several intriguing and fundamental aspects of debonding at soft interfaces, including the formation and persistence of regularly arranged nanocavities and bridges, "adhesion-debonding hysteresis" and vastly lower adhesive strengths compared to the absence of pattern formation. The analysis shows the hysteresis to be caused by an energy barrier that separates the metastable patterned configuration during withdrawal, and the debonded state. The metastable morphological pathways involving cavitation and peeling of contact zones engender substantially lower debonding forces.