Maghsoodi Neda, Bhattacharya Kaushik
Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA.
Soft Matter. 2024 Dec 18;21(1):39-44. doi: 10.1039/d4sm00606b.
Reversible dry adhesion is exploited by lizards and insects in nature, and is of interest to robotics and bio-medicine. In this paper, we use numerical simulation to study how the soft elasticity of liquid crystal elastomers can affect its adhesion and provide a technological opportunity. Liquid crystal elastomers are cross-linked elastomer networks with liquid crystal mesogens incorporated into the main or side chain. Polydomain liquid crystalline (nematic) elastomers exhibit unusual mechanical properties like soft elasticity, where the material deforms at nearly constant stress, due to the reorientation of mesogens. Our study reveals that the soft elasticity of nematic elastomers dramatically affects the interfacial stress distribution at the interface of a nematic elastomer cylinder adhered to a rigid substrate. The stress near the edge of the nematic cylinder under tensile load deviates from the singular behavior predicted for linear elastic materials, and the maximum normal stress reduces dramatically. This suggests that nematic elastomers should display extremely high, but controllable adhesion, consistent with the available experimental observations.
自然界中的蜥蜴和昆虫利用了可逆干粘附，这在机器人技术和生物医学领域具有重要意义。在本文中，我们通过数值模拟研究液晶弹性体的软弹性如何影响其粘附性，并提供一种技术契机。液晶弹性体是将液晶介晶掺入主链或侧链的交联弹性体网络。多畴液晶（向列型）弹性体表现出诸如软弹性等异常的机械性能，由于介晶的重新取向，材料在几乎恒定的应力下发生变形。我们的研究表明，向列型弹性体的软弹性极大地影响了粘附在刚性基底上的向列型弹性体圆柱体界面处的界面应力分布。在拉伸载荷下，向列型圆柱体边缘附近的应力偏离了线性弹性材料预测的奇异行为，并且最大正应力大幅降低。这表明向列型弹性体应表现出极高但可控的粘附性，这与现有的实验观察结果一致。
