Bioinspired Metastable Transient Peeling for Repeatable Rapid Release

Reversible adhesives must hold securely yet release quickly, but conventional designs regulate adhesion only in the strength domain, leaving holding and release in direct conflict. This trade-off limits damage-free handling of ultrathin, brittle materials such as silicon wafers. Inspired by the explosive seed ejection of the squirting cucumber (Ecballium elaterium), we introduce metastable transient peeling (MTP), which regulates when stored interfacial energy is released. A preload establishes a metastable contact with a tunable energy barrier, and a minute perturbation then triggers self-accelerated, edge-synchronous peeling; a four-parameter mechanics framework links material and operating variables to performance. A viscoelastic hemispherical gripper releases within 52 ms, retains over 85% of its release performance after 300 000 cycles, and performs 10 000 damage-free pick-up, transfer, and release operations on 45-µm-thick silicon wafers while remaining operative at 10 Pa. MTP establishes temporal-domain control as a route to fast, clean, repeatable release.