调控界面应力分布增强干黏附材料的黏附力  

Enhanced Adhesion of Dry Adhesives through Interface Stress Distribution Control

作　　者：李昊宇 王涛[1,2] 陈子健 赵旸 辜萍 LI Haoyu;WANG Tao;CHEN Zijian;ZHAO Yang;GU Ping(CAS Key Laboratory of Mechanical Behavior and Design of Materials,Hefei 230027,China;Department of Precision Machinery&Precision Instrumentation,University of Science and Technology of China,Hefei 230026,China;Department of Modern Mechanics,University of Science and Technology of China,Hefei 230027,China;State Key Laboratory of Fire Science,University of Science and Technology of China,Hefei 230027,China)

机构地区：[1]中国科学院材料力学行为和设计重点实验室,合肥230027 [2]中国科学技术大学精密机械与精密仪器系,合肥230026 [3]中国科学技术大学近代力学系,合肥230027 [4]中国科学技术大学火灾科学国家重点实验室,合肥230027

出　　处：《功能高分子学报》2024年第5期424-432,共9页Journal of Functional Polymers

基　　金：国家自然科学基金(12272370,12172348)。

摘　　要：干黏附材料利用分子间作用力产生黏附性能,凭借其可重复使用等特点,在机器人技术及精密制造中有着重要的应用。为使干黏附材料受拉时接触界面应力更加均匀,提高其黏附力,对微米级羰基铁粉颗粒/聚二甲基硅氧烷磁流变弹性体干黏附材料进行结构设计,通过改变羰基铁粉的质量分数和外加磁场,制备了弹性模量沿半径方向变化的多级复合样品和梯度模量样品,黏附强度分别达到8.0 N/cm^(2)和11.4 N/cm^(2),相较于羰基铁粉质量分数(60%)相同的均质样品,多级复合样品和梯度分布样品的黏附强度分别提升了35%和77%。结合有限元仿真结果可知,弹性模量径向分布设计能有效降低边缘应力集中,由于梯度模量样品界面正应力分布更均匀,因此其黏附增强效果比多级复合样品更显著。In contrast to conventional chemical adhesives,dry adhesive materials acquire adhesion by surface interactions such as van der Waals forces rather than chemical bonding.Dry adhesive materials demonstrate a wide range of applications across multiple areas owing to their simplicity in preparation and recyclability.For instance,biomimetic robots inspired by creatures like geckos exploit dry adhesive materials for space or outdoor scenarios.These materials are used in medical equipment,wearable materials,and transfer printing of micro/nano devices.However,when dry adhesive materials are subjected to normal tensile force,they may experience stress concentration at the edge of their contact interface with the substrate,which results in an adhesive strength being less than the theoretical value.To address this issue,this study designed micrometer-scale carbonyl iron powder particles/polydimethylsiloxane magnetorheological elastomer-based dry adhesive materials.By adjusting the mass fraction of carbonyl iron powder and applying an external magnetic field,disk-like composites in centimeter scale with variable Young's modulus along the radial direction in stages or continuously were prepared.The adhesive strength of the two test samples reached 8.0 N/cm^(2) and 11.4 N/cm^(2),respectively,which was 35%and 77%higher than that of control samples with the same carbonyl iron powder mass fraction(60%).Based on finite element simulation,the radial distribution of Young's modulus effectively reduces stress concentration along the edge region,which in turn homogenizes the normal stress distribution at interfaces,thus enhancing normal adhesion performances.Comparing to homogeneous and multi-stage composites,the continuously varying modulus samples exhibited a more uniform normal stress distribution at the interface,which further improved adhesion.Our design of radial distribution of modulus over dry adhesive materials and the achievement of a continuously change of modulus through spatial distribution of magnetic fields provides val

关 键 词：磁流变弹性体 干黏附材料 弹性模量 有限元仿真 应力分布 

分 类 号：TH145.41[一般工业技术—材料科学与工程]