Reversible Adhesion via Light-Regulated Conformations of Rubber Chains

Abstract

Bio-inspired reversible adhesives have attracted great attention because of their promising applications in the electronic, biomedical, and robotic fields. Here, to achieve in situ reversible adhesion, a new concept is demonstrated by modulating the conformations of polydimethylsiloxane (PDMS) chains. The new adhesive, termed BGPP, is composed of the graphene/PDMS composite (GP) as the backing layer and PDMS as the micropillar array. The photothermal effect of graphene under UV irradiation heats up the micropillars, resulting in an increase in the chain conformations of PDMS and thus the contact points with the counterpart surface. The more contact points together with the alignment of PDMS chains during the shearing result in an adhesion much higher than that without UV irradiation. The adhesion switching thus does not rely on the changing of the contact area, and so the macroscopic deformation of structures is avoided. The results suggest a new design principle for light-controllable structured adhesive, which could be conceptualized into other rubbery materials.

Tree Frog‐Inspired Structured Hydrogel Adhesive with Regulated Liquid

“…It is quite different from previously reported frog‐inspired wet adhesives, which usually possess a smooth pillar top with roughness of ≈1.2 nm. [ 7b,12 ] As the epithelial cells on the toe pad of tree frogs consist of a dense array of nanopillars with concave tips, [ 13 ] SHAD has a better chance to mimic the tree frog toe pad. Moreover, the PAAm/PVA micropillar is porous inside (Figure 1e), that the liquid in SHAD not only covers the whole surface, but also connects to the liquid inside SHAD.…”

Tree frog-inspired nanopillar arrays for enhancement of adhesion and friction

“…[1][2][3][4][5][6][7][8][9][10][11] The geometry of the pillar array allows conformal contacts to rough surfaces, generating strong adhesions. [12][13][14] Compared to the great attention on geckos, much less attention has been paid to the tree frogs which are able to strongly attach and smoothly climb on rough/ smooth surfaces under dry/wet conditions. 5,8,15 Patterned surfaces on the toe pads are demonstrated to act a critical role in their performance.…”

Exploiting Synergistic Experimental and Computational Approaches to Design and Fabricate High-Performance Elastomer

“…One of the most commonly used SRs, polydimethylsiloxane (PDMS), exhibits excellent bulk properties , and has a very low T g (approximately equal to −124 °C). − However, its crystallization temperature is relatively high at −73 °C , and its temperature of the mesocrystalline phase transition is even higher at −10 °C to approximately −20 °C , which is close to the cold winter temperature in the northern hemisphere. This indicates that PDMS is fragile below such temperatures, which seriously limits its application in the extremely low-temperature environment.…”