Why pens have rubbery grips
Why pens have rubbery grips
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DOI：
10.1073/pnas.1706233114
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发表时间：
2017-10-10
影响因子：
11.1
通讯作者：
Adams, Michael J.
中科院分区：
文献类型：
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作者：
Dzidek, Brygida;Bochereau, Serena;Adams, Michael J.
人类手指与光滑、坚硬物体稳定接触的过程令人惊讶地缓慢。使用高分辨率成像，我们发现，当按压玻璃时，手指垫脊部的实际接触随着时间的推移遵循一级动力学关系演变。这种进化是皮肤角质层的角蛋白和玻璃表面之间的微观连接的两个阶段结合过程的结果。这一过程是由汗腺分泌水分推动的，因为角质层中水合作用的增加会使其变得更软。无论手指的初始湿度状态和施加的法向力如何，在加载触点后的20 S内通常都会达到饱和。因此，在握力和知觉研究中经常用作基准量的总接触面积不能很好地反映人类手指与光滑、不透水的表面之间发生的实际接触机制。相反，如果相对干燥状态下的角蛋白而言，对接表面是柔软的，则稳定接触区域的形成几乎是瞬间的。正是由于这个原因，弹性体通常被用来涂覆握把表面。
The process by which human fingers gives rise to stable contacts with smooth, hard objects is surprisingly slow. Using high-resolution imaging, we found that, when pressed against glass, the actual contact made by finger pad ridges evolved over time following a first-order kinetics relationship. This evolution was the result of a two-stage coalescence process of microscopic junctions made between the keratin of the stratum corneum of the skin and the glass surface. This process was driven by the secretion of moisture from the sweat glands, since increased hydration in stratum corneum causes it to become softer. Saturation was typically reached within 20 s of loading the contact, regardless of the initial moisture state of the finger and of the normal force applied. Hence, the gross contact area, frequently used as a benchmark quantity in grip and perceptual studies, is a poor reflection of the actual contact mechanics that take place between human fingers and smooth, impermeable surfaces. In contrast, the formation of a steady-state contact area is almost instantaneous if the counter surface is soft relative to keratin in a dry state. It is for this reason that elastomers are commonly used to coat grip surfaces.