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，带电聚合物是非常柔性的，并且不具有强的机械性能。 该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Kevlar（R））和一种离子液体（也称为熔盐）的混合物形成。 这种被称为分子离子复合材料（MIC）的新材料结合了固体和液体的最佳特性。 MIC材料是坚硬且不易燃的固体，但它们可以以非常低的电阻传导锂和钠等离子，就像离子在液体中一样。 MIC的特性也可以广泛定制，以用于不同的应用，如净水器，机电传感器或人造肌肉。 该项目将结合联合收割机尖端的研究工具，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。 通过结合此类跨学科知识和见解，这些研究人员将努力为更安全、更便宜、更轻便的锂电池等设备的MIC材料创造新的设计。 该项目有望为先进的电池材料技术提供支持，从而为美国企业对200亿美元全球电池市场的影响开辟了一条潜在的新途径。 参与该项目的学生和合作者将获得有关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教育推广计划中传播给K-12儿童及其父母。技术摘要：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，但其中高密度的离子就像在液体中一样移动。 它建立在一类新的聚合物离子导体的发现，被称为分子离子复合材料（MIC）。 由刚性棒含阴离子的聚合物和离子液体（IL）形成的原型MIC表现出以下可调性质的特殊组合：高达8 mS/cm的离子电导率、广泛可调的弹性模量（0.01#8722;3 GPa）和高达300 ℃的热稳定性。 MIC显示出允许在锂和钠电池中使用金属电极的前景，可能实现更高的能量密度以及在宽温度范围内的电池操作，并具有固有的耐火性。 虽然这些材料显示出令人印象深刻的特性，但研究人员才刚刚开始了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。 该项目结合了基本的聚合物分析，包括核磁共振（NMR），X射线散射和显微镜与分子动力学模拟和理论的传导和定向物质。 更好地理解MIC的基本性质可以用于设计新的组合物，以满足电池电解质或其他分子分离应用的期望要求。 参与该项目的学生和合作者将获得有关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，并传播到K-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。

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.