GOALI: A Multiscale Approach on Interfacial and Structural Interlocking Between Polymer Grafted Shape Memory Pillars

技术概述：该奖项基于互补的研究活动，包括宾夕法尼亚大学材料科学与工程（MSE）杨实验室的聚合物合成、制造和表征，宾夕法尼亚大学材料科学与工程（MSE）李实验室在宾夕法尼亚大学/MSE的分子和元结构（有序阵列）水平的理论建模，以及通用汽车全球研究与发展中心（GM）谢实验室的合作。它建立在他们的知识在形状记忆聚合物（SMP）化学和表面化学对稳健和工业规模的粘附。本提案的重点是关于表面化学，地形和顺应性在不同长度尺度上对粘附性的单独和综合作用的根本未解决的问题。具体来说，pi计划：(1)制造精确控制尺寸、纵横比和间距的SMP柱阵列；(2)接枝控制良好的聚合物刷来操纵分子相互作用（如氢键和离子- π相互作用），以实现成键和脱键；(3)系统地研究了变形和恢复作用下互补SMP柱的粘附和剥落；(4)将实验结果与各相关长度尺度的多尺度建模结果进行比较，建立了互锁干粘附的完整机理观点。非技术概述：聚合物之间的粘合在广泛的工业应用中起着重要作用。液体基胶粘剂具有很强的附着力，但是它们的热固化是能量密集型的，附着力通常是不可逆转的。大自然为我们提供了可逆性干燥粘附的显著例子，牛蒡种子和壁虎脚毛就体现了这一点，它们的粘附不需要液体或长时间的固化。本提案旨在开发仿生超胶样，但可修复的干燥粘合剂。它不仅将提供重要的科学见解，而且还将影响广泛的技术，包括电子封装，汽车和飞机组件以及软机器人。通过新的培训和拓展机会，各个层次的学生都将接触到化学、材料科学与工程、软力学、纳米制造和计算建模等各种主题，包括通用汽车工业研究员的暑期讲座、将研究成果整合到课程中、高中生和本科生通过暑期研究和高级设计项目的参与。通用汽车全球研发中心博士生行业实习。研究成果也将创造一个重要的机会，激发公众的兴趣，从而激发他们对科学、技术、工程和数学（STEM）的兴趣。

TECHNICAL SUMMARY:The award is based on complementary research activities, including polymer synthesis, fabrication and characterization in Yang's lab in Materials Science and Engineering (MSE) at the University of Pennsylvania (Penn), theoretical modeling at the molecular and meta-structural (ordered array) levels in Li's lab at Penn/MSE, in collaboration with Xie's lab at General Motors Global Research & Development Center (GM). It builds upon their knowledge in shape memory polymer (SMP) chemistry and surface chemistry toward robust and industrial scale adhesion. The focus of this proposal is on the fundamentally unresolved question concerning the individual and combined roles of surface chemistry, topography, and compliance on adhesion at different length scales. Specifically, the PIs plan to: (1) fabricate SMP pillar arrays with precise control over size, aspect ratio, and spacing; (2) graft well-controlled polymer brushes to manipulate molecular interactions (e.g. H-bonding and ion-pi interactions) for both bonding and debonding; (3) systematically study adhesion and peeling off on complementary SMP pillars under deformation and recovery, and (4) compare experimental results with multiscale modeling throughout each relevant lengthscale and develop a complete mechanistic view of interlocking dry adhesion. NON-TECHNICAL SUMMARY:Adhesion between polymers plays an important role in a wide range of industrial applications. Liquid based adhesives offer strong adhesion, however their thermal curing is energy intensive and the adhesion is generally not reversible. Nature provides us with remarkable examples of reversible dry adhesion as manifested in burdock seeds and gecko foot hairs, where no liquid or lengthy curing is involved in the adhesive attachment. This proposal seeks to develop biomimetic superglue-like, yet reworkable, dry adhesives. It will not only provide important scientific insights, but also impact a wide range of technologies, including electronic packaging, automotive and airplane assemblies, and soft robotics. Students at all levels will be exposed to a diverse range of topics in chemistry, materials science and engineering, soft mechanics, nanofabrication and computational modeling through new training and outreach opportunities, including summer lectures by the industrial researcher from General Motors, integration of the research outcome in courses, engagement of high school and undergraduate students through summer research and senior design projects, and industrial internship by a PhD student at General Motors Global R&D Center. The research outcome will also create a significant opportunity to excite the general public, thereby engaging their interest in Science, Technology, Engineering, and Mathematics (STEM).