Collaborative Research: Structure-Mechanics Relationships for Ultra-thin Block Copolymer Films

该合作项目汇集了马萨诸塞大学阿姆赫斯特分校和宾夕法尼亚大学的科学家，以获得关于当聚合物材料被制成厚度接近单个分子大小的薄膜时，机械性能（如刚度和强度）如何变化的新理解。超薄薄膜，比如在这个项目中研究的那些，被期望有助于减少过滤等过程中的能耗，以及半导体制造。然而，目前的材料无法在这些应用中提供足够的强度。新的实验方法将与分子模拟相结合，以了解聚合物薄膜中的结构如何影响它们在这些高度受限状态下的性能。除了与新的基础科学和材料设计指南的发展相关的广泛影响，将减少材料浪费和提高能源效率，该项目将通过丰富的、涉及实验和模拟的合作研究经验，为培养博士生、本科生和高中生提供新的机会。本合作项目将提供关于嵌段共聚物畴结构在控制超薄聚合物薄膜的完全机械响应中的作用的新的基础数据和知识，其中薄膜厚度相当于或小于畴结构尺寸尺度。所提出的方法结合了先进的模拟和新颖的实验方法的优势，以测试基于受限材料中位置对段迁移率和链间纠缠的作用的新假设，以及对机械性能的相应影响。在实验上，一种最新的机械测量方法，称为超薄薄膜单轴拉伸测试仪（TUTTUT），将用于量化超薄嵌段共聚物薄膜的力学。实验将与模拟相结合，使用粗粒度模型来预测聚合物膜的分子响应，模拟将提供缠结网络变化的局部图像和局部动力学，作为距离嵌段共聚物膜中界面的位置的函数。通过这些努力，这些合作项目将支持下一代材料科学家和工程师的教育、培训和激励，重点是增加妇女和传统上代表性不足的少数民族的参与。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

PART 1: NON-TECHNICAL SUMMARYThis collaborative project brings together scientists at the University of Massachusetts Amherst and the University of Pennsylvania to gain new understanding of how mechanical properties, like stiffness and strength, change when a polymeric material is made into a film with thickness near the size of an individual molecule. Ultra-thin films, such as the ones studied in this project, are desired to help decrease energy consumption in processes like filtration, as well as in semiconductor manufacturing. However, current materials are unable to provide sufficient strength in these applications. New experimental methods will be combined with molecular simulations to understand how structures in the polymer thin films affect their properties in these highly confined states. Beyond the broad impact related to the development of new fundamental science and materials-design guidelines that will decrease materials waste and increase energy efficiency, this project will provide new opportunities for educating Ph.D. students, undergraduate students, and high-school students through rich, collaborative research experiences involving both experiments and simulations.PART 2: TECHNICAL SUMMARYThis collaborative project will provide new fundamental data and knowledge on the role of block copolymer domain structure in controlling the full mechanical response of ultra-thin polymer films, where film thickness is comparable to or smaller than the domain structure size scale. The proposed approach unites the strengths of advanced simulations and novel experimental methods to test new hypotheses based on the role of position within a confined material on segmental mobility and inter-chain entanglements, and the consequential impact on mechanical properties. Experimentally, a recent mechanical measurement method, called The Uniaxial Tensile Tester for Ultra-Thin films (TUTTUT), will be used to quantify the mechanics of ultra-thin block copolymer films. The experiments will integrate with simulations that use coarse-grained models to predict the molecular response of polymer films, and the simulations will provide a local picture of the changes in the entanglement network and local dynamics as a function of position away from the interfaces in the block copolymer films. Through these efforts, the co-PIs will support the education, training, and inspiration of the next generation of materials scientists and engineers, with a focus toward increased participation of women and traditionally under-represented minorities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.