RII Track-4:NSF: Atomic-Scale Understanding of the Self-Healing Mechanisms of Ionic Polymers

随着一次性塑料使用量的增加，塑料污染已成为社会面临的最紧迫的环境问题之一。开发坚固和可回收的一次性塑料替代品将大大减少塑料垃圾。减少塑料垃圾的一种方法是开发自我修复的离子聚合物，这种聚合物可以抵抗永久性损害。尽管在自愈离子聚合物的研究上投入了大量的努力，但产生最佳自愈性能的主要机制仍然不清楚。该奖学金的目标是在原子尺度上了解离子聚合物的自愈机制。这一目标将通过由主办实验室橡树岭国家实验室开发的高精度大规模加速分子动力学模拟技术来实现。这种技术将使PI和她的研究生和本科生能够仔细检查离子聚合物的相互作用，以全面了解它们的自我修复过程，同时也增强了PI实验室的研究能力。然后，研究概念将通过将研究成果纳入PI的本科生材料科学课程并通过公共推广计划与年轻一代交流来传递给更广泛的受众。该奖学金项目的成果将发表在期刊文章和会议上，这将扩大公众对佛蒙特州大学的认识，并提高该大学的声誉。这项奖学金还将加强佛蒙特州大学和橡树岭国家实验室之间的联系，并将在未来促进两个机构之间潜在的新合作。这项建议的总体目标是对离子聚合物的自愈机制有一个清晰和全面的原子尺度了解，旨在增强它们的自愈性能。为了实现这一总体目标，PI将基于聚合物结构和动力学的原子建模，在聚合物和离子组成及其自愈性能之间建立明确的关系。原子相互作用和反应动力学将通过一种精确而有效的方法来研究，即基于长程修正(LC)密度泛函紧束缚(DFTB)理论的线性标度碎片分子轨道(FMO)方法，该方法非常适合于研究离子聚合物。对不同离子聚合物组成的自愈机制的物理理解将加速高性能材料的选择、合成和制造，以实现可持续应用。作为副产品，通过FMO-LC-DFTB分子动力学模拟获得的动态信息可以用于分析它们的离子输运性质，这在柔性电子学中也是特别感兴趣的。这项拟议的工作将扩大PI跨不同学科的知识和技能范围，并将刺激佛蒙特州大学材料科学研究的研究竞争力。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Plastic pollution has become one of the most pressing environmental issues facing society due to the growing usage of disposable plastics. Developing sturdy and recyclable substitutes for single-use plastics will significantly reduce plastic waste. One way to reduce plastic waste is to develop self-healing ionic polymers that are resistant to permanent damage. Despite a massive amount of effort devoted to self-healing ionic polymer studies, the main mechanisms that yield optimal self-healing performance remain obscure. The goal of this fellowship is to provide an atomic-scale understanding of the self-healing mechanisms of ionic polymers. This aim will be achieved via a highly accurate large-scale accelerated molecular dynamics simulation technique developed at the host lab, Oak Ridge National Laboratory. Such a technique will allow the PI and her graduate and undergraduate students to closely examine the interaction of ionic polymers to acquire a complete understanding of their self-healing process while also enhancing the research capabilities of the PI’s lab. Research concepts will be then delivered to a broader audience by incorporating research outcomes to the PI's undergraduate materials science class and communicating to the younger generation through public outreach programs. Results from this fellowship project will be published in journal articles and conferences, which will expand the public's awareness of the University of Vermont and enhance the university’s reputation. This fellowship will also strengthen the connection between the University of Vermont and Oak Ridge National Laboratory and will incite potential new collaborations between the two institutions in the future.The overarching goal of this proposal is to obtain a clear and holistic atomic-scale understanding of the self-healing mechanisms of ionic polymers, aimed to enhance their self-healing performance. To achieve this overarching goal, the PI will establish a clear relationship between polymer and ion compositions and their self-healing performance based on atomistic modeling of polymer structure and dynamics. Atomic interactions and reactive dynamics will be investigated via an accurate and efficient methodology, i.e., the linear-scaling fragment molecular orbital (FMO) method based on long-range corrected (LC) density-functional tight-binding (DFTB) theory, which is highly suitable for studying ionic polymers. The physics-based understanding of the self-healing mechanisms for different ionic polymer compositions will accelerate high-performance materials selection, synthesis, and manufacturing for sustainable applications. As a byproduct, the dynamic information obtained via the FMO-LC-DFTB molecular dynamics simulations can be used to analyze their ionic transport properties, which are also of particular interest in flexible electronics. This proposed work will expand the PI’s scope of knowledge and skillset across various disciplines and will stimulate the research competitiveness in materials science studies at the University of Vermont.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.