Department of Mechanical Engineering, University of Akron, Akron, OH 44325, USA.
J R Soc Interface. 2012 Nov 7;9(76):2781-90. doi: 10.1098/rsif.2012.0108. Epub 2012 Jun 13.
Gecko toe pads show strong adhesion on various surfaces yet remain remarkably clean around everyday contaminants. An understanding of how geckos clean their toe pads while being in motion is essential for the elucidation of animal behaviours as well as the design of biomimetic devices with optimal performance. Here, we test the self-cleaning of geckos during locomotion. We provide, to our knowledge, the first evidence that geckos clean their feet through a unique dynamic self-cleaning mechanism via digital hyperextension. When walking naturally with hyperextension, geckos shed dirt from their toes twice as fast as they would if walking without hyperextension, returning their feet to nearly 80 per cent of their original stickiness in only four steps. Our dynamic model predicts that when setae suddenly release from the attached substrate, they generate enough inertial force to dislodge dirt particles from the attached spatulae. The predicted cleaning force on dirt particles significantly increases when the dynamic effect is included. The extraordinary design of gecko toe pads perfectly combines dynamic self-cleaning with repeated attachment/detachment, making gecko feet sticky yet clean. This work thus provides a new mechanism to be considered for biomimetic design of highly reuseable and reliable dry adhesives and devices.
壁虎的脚趾垫能在各种表面上产生很强的附着力，但在日常污染物周围却能保持非常干净。了解壁虎在运动中如何清洁脚趾垫对于阐明动物行为以及设计具有最佳性能的仿生装置至关重要。在这里，我们测试了壁虎在运动中的自清洁能力。据我们所知，我们首次提供了壁虎通过独特的动态自我清洁机制通过数字超伸展来清洁脚部的证据。当自然行走时进行超伸展，壁虎从脚趾上脱落污垢的速度是不进行超伸展行走的两倍，只需四个步骤就可使它们的脚恢复到近 80%的原始粘性。我们的动力学模型预测，当刚毛突然从附着的基质上释放时，它们会产生足够的惯性力将附着的匙突上的污垢颗粒从附着物上移开。当包括动态效应时，预测的污垢颗粒的清洁力显著增加。壁虎脚趾垫的卓越设计完美地结合了动态自清洁和重复的附着/脱离，使壁虎的脚保持粘性但又干净。这项工作为仿生设计提供了一种新的机制，可用于设计高度可重复使用和可靠的干式粘合剂和装置。
