EAGER: High-Gradient-Strength NMR Accessories for Transport Measurements in Advanced Nanomaterials and Microstructures

1142111 Leisen探索性研究（EAGER）项目的早期概念资助的目标是研究（i）生成功能化纳米管的汤中的反应物物种，（ii）设计纳米管中的探针分子，（iii）工程微接触器中的流体，（iv）具有多环拓扑结构的大分子，以及（v）阴离子交换燃料电池中的阴离子的分子水平传输。 这些研究将通过扩散核磁共振（NMR）进行，使用在该赠款支持下获得的专用设备（高梯度强度扩散探针和梯度放大器）在现有的NMR光谱仪上进行。 由此产生的新的实验能力是迫切需要的，使流体动力学，分离，纳米和微流体，纳米工程，能量转换和燃料电池开发的探索性研究。 拟议活动的智力价值体现在需要强梯度NMR扩散测量的研究重点中：（i）纳米管生长和工程的机理研究-所需的NMR附件将能够测量纳米颗粒的尺寸和结构，从而对在水溶液中制备的单壁无机纳米管的生长机制产生重要的洞察力。这些知识对于纳米管的发展至关重要，纳米管在电子，分离和能源存储/发电/管理等各种转型技术中得到应用。(ii)纳米管中的传输-尽管具有科学和技术意义，但人们对管状材料中的纳米流体传输知之甚少。无机纳米管（基于金属氧化物）和有机纳米管（基于交联环糊精）是纳米管膜和生物纳米通道的良好模型系统。这些纳米管内的探针分子的NMR扩散测量将提供传统技术无法实现的重要见解。(iii)用于大阵列微接触器的分层工程织物工程织物为（生物）化学分离的不混溶流体的液-液接触提供了一种新颖且高度可扩展的方法。 该技术的发展需要多相流的传输测量和三维两亲性微通道的孔结构表征。(iv)拓扑复杂流体中的动力学-由于非常规缠结的存在，相对于线性聚合物，环状和多环大分子的扩散知之甚少。这些拓扑结构复杂的大分子与线性聚合物的共混物的扩散行为的调查将是关键，在解开分子拓扑结构的聚合物动力学的基本方面的影响。(v)阴离子交换膜中的传输-正在开发采用阴离子交换膜的燃料电池设计，以克服现有质子交换膜的缺点。为了优化这些膜，必须研究氢氧化物离子和水在具有非均匀形态的阳离子聚合物膜中的扩散。更广泛的影响：NMR扩散附件将使研究成为开发和理解具有变革潜力的材料、工艺和技术的关键，如化学加工和能源管理。 无机和有机纳米管、廉价的织物微接触器和阴离子交换膜的重要突破可能对经济发展产生广泛影响。 拟议的设备是一个适度的投资，是至关重要的，使探索性研究在所有这些？高风险高回报并提供独特的跨学科优势。 所要求的设备将大大提高大亚特兰大地区各领域大批研究人员的一般研究能力。

1142111LeisenThe objective of this Early-Concept Grant for Exploratory Research (EAGER) project is to investigate molecular-level transport of (i) reactant species in soups that generate functionalized nanotubes, (ii) probe molecules in designed nanotubes, (iii) fluids in engineered micro-contacters, (iv) macromolecules with multicyclic topologies, and (v) anions in anion exchange fuel cells. These studies will be conducted by diffusion nuclear magnetic resonance (NMR) using specialized equipment acquired with support from this grant (high-gradient-strength diffusion probe and gradient amplifier) on an existing NMR spectrometer. The resulting new experimental capabilities are urgently needed to enable exploratory research in fluid dynamics, separations, nano- and microfluidics, nanoengineering, energy conversion, and fuel cell development. The intellectual merit of the proposed activity is embodied in the research thrusts for which strong-gradient NMR diffusion measurements are needed:(i) Mechanistic studies of nanotube growth and engineering -The requested NMR accessories will enable measurements of size and structure of nanoparticles, thus yielding significant insight into growth mechanisms of single-walled inorganic nanotubes prepared in aqueous solution. This knowledge is crucial for the development of nanotubes, which find applications in various transformational technologies such as electronics, separations and energy storage/generation/ management.(ii) Transport in nanotubes - Nanofluidic transport in tubular materials is poorly understood, in spite of its scientific and technological relevance. Inorganic nanotubes (based on metal oxides) and organic nanotubes (based on crosslinked cyclodextrins) are good model systems for nanotube membranes and biological nanochannels. NMR diffusion measurements of probe molecules within these nanotubes will provide important insights that cannot be achieved with conventional techniques. (iii) Hierarchically engineered fabrics for large-array micro-contactors Engineered fabrics provide a novel and highly scalable approach to liquid-liquid contacting of immiscible fluids for (bio)chemical separations. Development of this technology requires transport measurements of multiphase flow and characterization of pore structure in 3D amphiphilic microchannels.(iv) Dynamics in topologically complex fluids - Diffusion of cyclic and multicyclic macromolecules is poorly understood relative to linear polymers due to the existence of unconventional entanglements. Investigation of the diffusion behavior of blends of these topologically complex macromolecules with linear polymers will be key in unraveling the effect of molecular topology on fundamental aspects of polymer dynamics.(v) Transport in anion exchange membranes - Fuel cell designs that employ anion exchange membranes are being developed to overcome shortcomings of existing proton exchange membranes. Diffusion of hydroxide ions and water confined in cationic polymer membranes with heterogeneous morphologies must be studied in order to optimize these membranes.Broader Impacts: The NMR diffusion accessories will enable research that is critical for development and understanding of materials, processes and technologies with transformative potential in areas like chemical processing and energy management. Important breakthroughs with inorganic and organic nanotubes, inexpensive fabric-based micro-contactors, and anion exchange membranes could have broad implications for economic development. The proposed equipment is a modest investment that is critical for enabling exploratory research within all of these ?high-risk high-payoff? areas and provides unique interdisciplinary leverage. The requested equipment will significantly enhance the general research capabilities of a large group of researchers across a variety of fields in the greater Atlanta area.