Water as a "glue": Elasticity-enhanced wet attachment of biomimetic microcup structures

Yue Wang, Zhengwei Li, Mohamed Elhebeary, Rene Hensel, Eduard Arzt, M. Taher

Research output: Contribution to journalArticlepeer-review


Octopus, clingfish, and larva use soft cups to attach to surfaces under water. Recently, various bioinspired cups have been engineered. However, the mechanisms of their attachment and detachment remain elusive. Using a novel microcup, fabricated by two-photon lithography, coupled with in situ pressure sensor and observation cameras, we reveal the detailed nature of its attachment/detachment under water. It involves elasticity-enhanced hydrodynamics generating "self-sealing" and high suction at the cup-substrate interface, converting water into "glue." Detachment is mediated by seal breaking. Three distinct mechanisms of breaking are identified, including elastic buckling of the cup rim. A mathematical model describes the interplay between the attachment/detachment process, geometry, elasto-hydrodynamics, and cup retraction speed. If the speed is too slow, then the octopus cannot attach; if the tide is too gentle for the larva, then water cannot serve as a glue. The concept of "water glue" can innovate underwater transport and manufacturing strategies.

Original languageEnglish (US)
Article numbereabm9341
JournalScience Advances
Issue number12
StatePublished - Mar 2022

ASJC Scopus subject areas

  • General


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