Self-Healable Thermoplastic Copolymers

自我修复是材料从物理损伤中恢复的能力。这项研究旨在提高我们在设计和开发具有自我修复特性的商品聚合物方面的有限知识。最终目标是开发新一代具有自主自愈能力的廉价高分子材料。计划的研究将影响聚合物和材料科学、聚合物工程和加工以及技术相关领域。据设想，由这些材料制成的现有聚合物和设备将在保持有用功能的同时使用更长时间。拟议研究的意义和重要性在于低成本材料在能源，医疗保健和国土安全部门的许多关键应用，所有这些都对美国的全球竞争力至关重要。该项目将制定科学方案，研究如何通过嵌入自修复特性来设计具有可持续和有用功能的聚合物材料。这些研究将包括设计和制备能够自我修复的热塑性商品聚合物。在有水和没有水的情况下，将对这些制备好的材料进行机械和化学完整性测试。测试的结果将用于进行计算机模拟，以努力了解自我修复的潜在过程。通过研究和教育的整合，新一代的多样化的研究生将成为社会的生产成员将被教育。这次培训将包括解决基本的科学问题，关于商品塑料如何配备自我修复功能，使它们变得可持续，并最大限度地减少废塑料的积累。第2部分：技术概述该项目的目标是使商品共聚物具有自修复性能，这将通过了解共聚物的组成和结构依赖于自修复的作用来实现。拟议的研究分为两个相互作用的研究领域：1)自愈的甲基丙烯酸酯/丙烯酸酯基含氟共聚物的共聚；2)阐明在静水压力下疏水和亲水性环境下控制自愈的分子水平过程的起源。一个最终的科学目标将是阐明起源和范德华（vdW）相互作用对自愈效率的强度。为了实现这些目标，一系列具有可变单体摩尔比的商品单体将被共聚。它们包括但不限于2,2,2-三氟甲基丙烯酸乙酯（TFEMA）、1,1,1,3,3,3,3 -六氟甲基丙烯酸异丙酯（HFIPMA）、2,2,2-三氟甲基丙烯酸丁酯（HFBMA）、2,2,2-三氟甲基丙烯酸乙酯（TFEMA）、1,1,1,3,3,3,3 -六氟甲基丙烯酸异丙酯/己基丙烯酸酯)（HFIPMA）和2,2,3,3,4,4,4-七氟甲基丙烯酸丁酯（HFBMA）)与丙烯酸基单体（正丁基、正戊基和正己基丙烯酸酯）共聚制成自愈膜。利用分子水平光谱（NMR， ESR， IR, Raman）和宏观探针（光学显微镜，拉伸和动态力学测量）支持分子动力学（MD）模拟，最终目标是开发新一代可自我修复的商品共聚物，并了解自我修复行为的分子起源。该奖项反映了NSF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 SUMMARYSelf-healing is the capability of a material to recover from physical damage. This research aims at advancing our limited knowledge on the design and development of commodity polymers that exhibit self-healing properties. An ultimate goal is the development of new generation of inexpensive polymeric materials that are capable of autonomous self-healing. The planned research will impact fields of polymer and materials science, polymer engineering and processing, as well as technologically related fields. It is envisioned that existing polymers and devices made out of these materials will last longer while sustaining useful functions. The significance and importance of the proposed research lies in numerous critical applications of low-cost materials in the energy, healthcare, and homeland security sectors, all of which are vital to US global competitiveness. This project will develop scientific protocols on how to design polymeric materials with sustainable and useful functions by imbedded self-healing properties. These studies will involve design and preparation of thermoplastic commodity polymers that are capable of self-healing. Such prepared materials will be tested for mechanical and chemical integrity during damage-repair cycles in the presence and absence of water. The output of the tests will be used to perform computer simulations in an effort to understand underlying processes of self-healing. Through the integration of research and education, a new generation of diversified graduate students who will become productive members of society will be educated. This training will include addressing fundamental scientific questions on how commodity plastics can be equipped with self-healing functions so they become sustainable and minimize waste plastics accumulation. PART 2: TECHNICAL SUMMARYThe goal of the project is to equip commodity copolymers with self-healing properties which will be accomplished by understanding the role of copolymer compositional and structural dependences on self-healing. The proposed studies are organized into two interactive research areas: 1) copolymerization of self-healing methacrylate/acrylate-based fluoro-containing copolymers and 2) elucidating the origin of molecular level processes that govern self-healing in the presence of hydrophobic and hydrophilic environments under hydrostatic pressures. An ultimate scientific objective will be to elucidate the origin and the strength of van der Waals (vdW) interactions on the efficiency of self-healing. To accomplish these objectives a series of commodity monomers with variable monomer molar ratios will be copolymerized. They include but are not be limited to 2,2,2-trifluoroethyl methacrylate (TFEMA), 1,1,1,3,3,3-hexafluoroisopropyl methacrylate (HFIPMA), 2,2,3,3,4,4,4-heptafluorobutyl methacrylate (HFBMA), 2,2,2-trifluoroethyl methacrylate (TFEMA), 1,1,1,3,3,3-hexafluoroisopropyl methacrylate/hexyl acrylate) (HFIPMA), and 2,2,3,3,4,4,4-heptafluorobutyl methacrylate (HFBMA) copolymerized with acrylic-based monomers (n-butyl, n-pentyl, and n-hexyl acrylates) to from self-healable films. Using molecular level spectroscopic (NMR, ESR, IR, Raman) and macroscopic probes (optical microscopy, tensile and dynamic mechanical measurements) supported by molecular dynamic (MD) simulations, an ultimate goal is to develop a new generation of self-healable commodity copolymers and understand molecular origins of self-healing behavior..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.