Snail epiphragm inspired intrinsically reversible superglues

January 3 – Febuary 28, 2021

Meeting Abstract

S8-10  Wed Jan 6 17:00 – 17:30  Snail epiphragm inspired intrinsically reversible superglues Yang, S*; Jolly, J; Cho, H; Wu, G; Fortoul, N; He, Z; Gao, Y; Jagota, A; University of Pennsylvania; University of Pennsylvania; University of Pennsylvania; University of Pennsylvania; Lehigh University; Lehigh University; University of Pennsylvania; Lehigh University

Adhesives are ubiquitous in daily life and industrial applications. There are two typical classes of adhesives: strong but irreversible (e.g., superglues) or reversible/re-usable but weak (e.g., pressure-sensitive adhesives and biological and biomimetic surfaces). Achieving both superstrong adhesion and reversibility has proven challenging. It has been shown that mucus secreted by snails allows them to maintain conformal contact with the rough surfaces of rocks or trees when they are active. Upon drying, a stiff epiphragm is formed, which interlocks with the target surface, rendering strong adhesion. Here, we report a hydrogel material system that provides superglue-like adhesion strength (up to 892 N cm-2) that is also reversible. The adhesion depends on the material’s intrinsic, especially, near-surface properties, and their switching in the wet vs. dry states, not its geometry; the mechanism is analogous to the action of the epiphragm of snails. It is applicable to both flat and rough target surfaces. We successfully demonstrate support of an adult human subject using two 2 cm2 samples. We further demonstrate the flexibility to prepare a hydrogel mesh with micron-sized through-holes that can glue two nanoporous membranes together without blocking the nanochannels. We also show selective detachment of morpho butterfly wing scales using the hydrogel pad without damaging the delicate scale that has hierarchical structures, a task that would otherwise be impossible using liquid glues, further supporting the importance of low near-surface modulus during contact. We currently look to translate the knowledge into other materials to show the generosity of our biomimetic engineering principle.

the Society for
Integrative &