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

该奖项是基于互补的研究活动，包括聚合物合成，制造和表征在杨的实验室材料科学与工程（MSE）在宾夕法尼亚大学（Penn），理论建模在分子和亚结构（有序阵列）水平在李的实验室在Penn/MSE，与谢的实验室在通用汽车全球研究开发中心（GM）合作。 它建立在他们的形状记忆聚合物（SMP）化学和表面化学知识，以实现强大的工业规模的粘附。该提案的重点是从根本上解决的问题，关于表面化学，地形，并遵守在不同的长度尺度上的附着力的单独和组合的作用。 具体而言，PI计划：（1）制造精确控制尺寸，纵横比和间距的SMP柱阵列;（2）接枝良好控制的聚合物刷以操纵分子相互作用（例如氢键和离子-π相互作用），用于键合和脱键;（3）系统地研究了在变形和恢复下互补SMP柱上的粘附和剥离，和（4）比较实验结果与多尺度模型在每个相关的长度尺度，并制定一个完整的机械联锁干粘合的观点。非技术总结：聚合物之间的粘合在广泛的工业应用中起着重要作用。基于液体的粘合剂提供强粘合，然而它们的热固化是能量密集型的，并且粘合通常是不可逆的。大自然为我们提供了可逆的干粘附的显著例子，如牛蒡种子和壁虎足毛，其中没有液体或长时间的固化涉及粘合剂附着。该提案旨在开发仿生超级胶水，但可重复使用的干粘合剂。它不仅将提供重要的科学见解，还将影响广泛的技术，包括电子封装，汽车和飞机装配以及软机器人。各级学生将通过新的培训和推广机会接触化学，材料科学与工程，软力学，纳米纤维和计算建模方面的各种主题，包括通用汽车工业研究员的夏季讲座，研究成果在课程中的整合，高中和本科生通过夏季研究和高级设计项目的参与，通用汽车全球研发中心的博士生进行的工业实习&。研究成果还将创造一个重要的机会，激发公众，从而吸引他们对科学，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).