Use of biomimetic hexagonal surface texture in friction against lubricated skin

Alexey Tsipenyuk,Michael Varenberg

doi:10.1098/rsif.2014.0113

Alexey Tsipenyuk, Michael Varenberg

Open Access

https://doi.org/10.1098/rsif.2014.0113

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Abstract

Smooth contact pads that evolved in insects, amphibians and mammals to enhance the attachment abilities of the animals' feet are often dressed with surface micropatterns of different shapes that act in the presence of a fluid secretion. One of the most striking surface patterns observed in contact pads of these animals is based on a hexagonal texture, which is recognized as a friction-oriented feature capable of suppressing both stick–slip and hydroplaning while enabling friction tuning. Here, we compare this design of natural friction surfaces to textures developed for working in similar conditions in disposable safety razors. When slid against lubricated human skin, the hexagonal surface texture is capable of generating about twice the friction of its technical competitors, which is related to it being much more effective at channelling of the lubricant fluid out of the contact zone. The draining channel shape and contact area fraction are found to be the most important geometrical parameters governing the fluid drainage rate.

Highlights

During the last decade, temporary attachment systems of terrestrial animals have become the focus of interdisciplinary scientific research aiming at revealing and possibly using functional principles underlying their amazing performance [1,2]
Hairy attachment systems have spurred much research that resulted in the appearance of a whole new direction dealing with the so-called ‘gecko adhesion’ effect with more than 500 papers devoted to the subject since 2000 [4]
Focusing on smooth contact pads evolved in insects, amphibians and mammals to enhance the attachment abilities of the animals’ feet [9,10,11], we see that they are often dressed with different surface micropatterns [12,13,14,15] acting in the presence of a fluid secretion, for example an oil-in-water emulsion in insects [16]

Summary

Introduction

Temporary attachment systems of terrestrial animals have become the focus of interdisciplinary scientific research aiming at revealing and possibly using functional principles underlying their amazing performance [1,2]. These systems are based on two important types of attachment pads relying on hairy or smooth architectures [3], which have received, different degrees of attention. On the other hand, have received far less attention, which, given their no less intriguing properties, for instance, high resistance to sliding [5,6,7,8], calls for further investigation.

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