Multi-Scale Self-Assembled Structure and Properties in Polymeric Molecular Composites

非技术概述：带电聚合物构成固体材料的基础，可用于在电池电解质中传导锂离子，或用于净化盐水或其他液体。通常，带电聚合物非常柔韧，没有很强的机械性能。这个项目涉及一种固体材料，由一种非常坚硬和强带电的聚合物（类似于凯夫拉(R)）和离子液体（也称为熔盐）的混合物形成。这种新材料被称为分子离子复合材料（MIC），它结合了固体和液体的最佳性能。MIC材料是坚硬的、不易燃的固体，但它们可以传导像锂和钠这样的离子，电阻很低，就像离子在液体中一样。mic的特性还可以广泛定制，以适应不同应用的潜在用途，如净水器、机电传感器或人造肌肉。该项目将结合尖端的研究工具，如核磁共振（NMR）和x射线分析，材料科学理论和计算分子模拟，以建立对MIC材料如何工作的基本理解。通过结合这些跨学科的知识和见解，这些研究人员将致力于为更安全、更便宜、更轻量的锂电池等设备创造新的MIC材料设计。该项目有望为先进的电池材料技术提供支持，从而为美国商业影响200亿美元的全球电池市场提供潜在的新途径。参与该项目的学生和合作者将获得关于这些新型聚合物导体的新知识，这些新知识将被整合到弗吉尼亚理工大学校园的聚合物科学课程中，并在弗吉尼亚州西南部的一个教育推广项目中传播给K-12儿童和他们的父母。技术概述：该项目旨在研究一种具有聚甲基丙烯酸甲酯模量的不易燃固体，但其内部高密度离子像液体一样移动。它建立在被称为分子离子复合材料（MICs）的新型聚合离子导体的发现之上。原型MICs由含有阴离子的刚性棒聚合物和离子液体（IL）组成，具有以下可调特性的特殊组合：离子电导率高达8 mS/cm，弹性模量(0.01&#8722；mic有望在锂电池和钠电池中使用金属电极，潜在地实现更高的能量密度，以及电池在宽温度范围内的工作，并具有固有的耐火性。虽然这些材料表现出令人印象深刻的特性，但研究人员才刚刚开始理解为什么如此快速的离子传输与如此坚硬和坚固的材料基质相称。这个项目结合了基本的聚合物分析，包括核磁共振（NMR）， x射线散射，分子动力学模拟和理论的传导和取向物质。更好地了解MICs的基本性质可以为新组合物的设计提供信息，以满足电池电解质或其他分子分离应用的所需要求。参与该项目的学生和合作者将获得关于这些新型聚合物导体的新知识，这些新知识将被整合到弗吉尼亚理工大学校园的聚合物科学课程中，并在弗吉尼亚州西南部的一个教育推广项目中传播给K-12儿童和他们的父母。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。

NON-TECHNICAL SUMMARY:Charged polymers form the basis of solid materials that can be used to conduct lithium ions in a battery electrolyte, or used to purify salt water or other liquids. Normally, charged polymers are very flexible and do not have strong mechanical properties. This project involves a solid material formed from a mixture of a very rigid and strong charged polymer (similar to Kevlar(R)) and an ionic liquid (also known as a molten salt). This new material, which is called a molecular ionic composite (MIC), combines the best properties of solids and liquids. MIC materials are stiff and non-flammable solids and yet they can conduct ions like lithium and sodium with very low resistance, as if the ions were in a liquid. The properties of MICs can also be widely tailored for potential use in different applications such as water purifiers, electromechanical sensors, or artificial muscles. This project will combine cutting edge research tools such as nuclear magnetic resonance (NMR) and X-ray analyses, materials science theories, and computational molecular simulations in order to build fundamental understanding of how MIC materials work. By combining such interdisciplinary knowledge and insights, these researchers will work to create new designs for MIC materials for devices such as safer, cheaper, and more lightweight lithium batteries. This project shows promise for feeding into advanced battery materials technology, thus enabling a potential new avenue for US business impact on the $20B global battery market. Students and collaborators involved in this project will gain new knowledge about these novel polymeric conductors, and this new knowledge will be integrated into polymer science classes on the Virginia Tech campus and propagated to K-12 children and their parents in an educational outreach program based in Southwest Virginia. TECHNICAL SUMMARY:This project aims at a non-flammable solid with the modulus of poly(methyl methacrylate), but where a high density of ions inside move as if they were in a liquid. It builds on the discovery of a new class of polymeric ion conductors that are termed molecular ionic composites (MICs). The prototypical MICs, formed from a rigid-rod anion-containing polymer and an ionic liquid (IL), exhibit the following special combination of tunable properties: ionic conductivity up to 8 mS/cm, widely tunable elastic modulus (0.01−3 GPa), and thermal stability up to 300 degrees C. MICs show promise for allowing use of metal electrodes in lithium and sodium batteries, potentially enabling higher energy density as well as battery operation over a wide temperature range and with inherent fire resistance. While these materials display impressive properties, researchers are only beginning to understand the origins of why such fast ion transport is commensurate with such a stiff and robust material matrix. This project combines fundamental polymer analyses involving nuclear magnetic resonance (NMR), X-ray scattering, and microscopy with molecular dynamics simulations and theories of conduction and oriented matter. Better understanding of the fundamental nature of MICs could feed into design of new compositions to meet desired requirements for battery electrolytes or other molecular separations applications. Students and collaborators involved in this project will gain new knowledge about these novel polymeric conductors, and this new knowledge will be integrated into polymer science classes on the Virginia Tech campus and propagated to K-12 children and their parents in an educational outreach program based in Southwest Virginia.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.