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Query: UMLS:C0001511 (Adhesion)
 5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adhesive pads on the legs of animals can be classified as either 'smooth' or 'hairy' (fibrillar). It has been proposed that the hairy design conveys superior and controllable adhesion. However, no study has yet compared the basic performance of both systems. As such, we measured single-pad friction and adhesion forces in sample hairy (Gastrophysa viridula) and smooth (Carausius morosus) pads and simultaneously recorded contact area. Adhesion and friction forces per unit pad area were very similar in smooth and hairy systems. Insect pads of both types adhere via a thin film of liquid secretion. As found previously for the smooth system, forces in the fibrillar system strongly decreased with larger amounts of fluid secretion present, suggesting that the fluid mainly serves to maximize contact on rough substrates. One essential prerequisite for the control of surface attachment during locomotion is the direction-dependence of adhesive pads. We compared the mechanisms of direction-dependence in smooth and hairy systems by performing proximal and distal slides. Both types of pad exhibited a large drop in friction when moved away from the body, although this effect was more extreme for the hairy system. Direction-dependence is explained in both smooth and fibrillar systems by the instability of the tarsal chain, causing the whole pad to peel off. In the fibrillar pads, anisotropy additionally arises from the direction-dependence of individual setae.
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PMID:Comparison of smooth and hairy attachment pads in insects: friction, adhesion and mechanisms for direction-dependence. 1884 Jun 68

Adhesion capabilities of various skin architectures found in nature can generate remarkable physical interactions with their engaged surfaces. Among them, octopus suckers have unique hierarchical structures for reversible adhesion in dry and wet conditions. Here, highly adaptable, biocompatible, and repeatable adhesive patches with unfoldable, 3D microtips in micropillars inspired by the rim and infundibulum of octopus suction cup are presented. The bioinspired synthetic adhesives are fabricated by controlling the meniscus of a liquid precursor in a simple molding process without any hierarchical assemblies or additional surface treatments. Experimental and theoretical studies are investigated upon to increase the effective contact area between unfoldable microtips of devices, and enhance adhesion performances and adaptability on a Si wafer in both dry and underwater conditions (max. 11 N cm-2 in pull-off strength) as well as on a moist pigskin (max. 14.6 mJ peeling energy). Moreover, the geometry-controlled microsuckers exhibit high-repeatability (over 100 cycles) in a pull-off direction. The adhesive demonstrates stable attachments on a moist, hairy, and rough skin, without any observable chemical residues.
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PMID:Highly Adaptable and Biocompatible Octopus-Like Adhesive Patches with Meniscus-Controlled Unfoldable 3D Microtips for Underwater Surface and Hairy Skin. 3012 35