UNS: Interfacial Properties of Nanoconfined Ionic Liquid

离子液体（Ionic liquids，IL）是一类相对较新的液体，它仅由阳离子和阴离子组成。典型离子液体的一些有用性质是其可忽略的低蒸气压、耐火性、优异的化学和热稳定性、宽的液体温度范围和宽的电化学窗口。由于这些优异的性质，离子液体已经被用于或考虑用于有机合成、催化、化学分离以及燃料和太阳能电池，并且它们的应用继续扩大。尽管出现了过多的涉及IL的过程，但是，与其他受限的材料类别，如聚合物，电解质溶液和液晶相比，对受限下的IL的界面性质，如流变性质和玻璃化转变温度的理解仍然非常有限。拟议的工作有两个目标：（i）获得描述离子液体的结构、粘度和玻璃化转变温度如何取决于限制程度的关系（分离）和（ii）获得对受限离子液体的分子参数，例如阳离子和阴离子的相对尺寸和形状以及受限表面的表面性质，例如表面电势和疏水性程度影响纳米限制下的上述性质。我们的主要假设是，当尺寸的限制变得可比的德拜屏蔽长度的离子液体，受限的玻璃化转变温度偏离体玻璃化转变温度。这一假设将主要用表面力装置技术进行测试，这是一种独特的技术，可以将分子研究与中尺度研究联系起来，也可以将其与大规模研究联系起来。这项工作将是第一个直接测量的粘度和玻璃化转变温度的离子液体下动态控制的纳米约束环境。从基础科学的角度来看，拟议中的工作是一个重要的一步，在了解的结构/性能关系的离子液体的约束。这样的理解可能最终导致新的基本见解系统的方法来选择一个离子对（S）的合理设计的离子液体在nanobinited环境下运行，并与所需的物理性能。该项目将首先提供关键的指导方针，以根据纳米约束下的重要界面特性按需选择理想类型的离子液体。这些知识将有助于优化和设计涉及受限离子液体的应用，如电池，太阳能电池和润滑剂。教育计划包括三个主要组成部分，将侧重于学生的研究监督，教学，辅导和推广与项目的研究组成部分接口。这些组成部分包括（i）开发一门新的研究生课程，由PI教授软物质的界面现象，（ii）指导研究中代表性不足的本科生，以及（iii）向阿克伦地区的公众传播项目成果，少数民族占总人口的25%，通过由NSF资助的教育电子设备开发赠款与当地高中教师建立联系。

#1511626Min, YounjinIonic liquids (ILs) are a relatively new class of liquids that consist only of cations and anions. Some of the useful properties of typical ILs are their negligibly low vapor pressure, fire resistance, excellent chemical and thermal stability, wide liquid temperature ranges, and wide electrochemical windows. Given these excellent properties, ILs have been used or considered for use in organic synthesis, catalysis, chemical separation, and fuel and solar cells, and their applications continue to expand. Despite a plethora of emerging processes involving ILs, however, an understanding of the interfacial properties of ILs under confinement, such as rheological properties and glass transition temperatures, remain very limited compared with that of other confined material classes, such as polymers, electrolyte solutions, and liquid crystals. The objective of the proposed work is twofold: (i) to obtain relationships describing how the structure, viscosity, and glass transition temperature of ILs depend on degree of confinement (separation) and (ii) to obtain a fundamental understanding of how the molecular parameters of confined ILs, such as the relative sizes and shapes of cations and anions and the surface properties of confining surfaces, such as surface potential and degree of hydrophobicity, affect the abovementioned properties under nanoconfinement. Our main hypothesis is that when the dimension of confinement becomes comparable to the Debye screening length of ILs, the confined glass transition temperature deviates from the bulk glass transition temperature. This hypothesis will primarily be tested with the surface forces apparatus technique, which is a unique technique that can link molecular studies to meso-scale studies and also to bulk-scale studies. This work will be first of its kind to directly measure the viscosity and glass transition temperature of ILs under dynamically controlled nanoconfined environments. From a fundamental science perspective, the proposed work represents an important step in understanding the structure/property relationships of ILs under confinement. Such an understanding may ultimately lead to new fundamental insights into a systematic method to select an ion pair(s) for the rational design of ILs operating under nanoconfined environments and with the desired physical properties. This project will first provide pivotal guidelines to select desirable types of ILs on demand on the basis of their important interfacial properties under nanoconfinement. Such knowledge will be useful to optimize and design applications involving confined ILs, such as batteries, solar cells, and lubricants. The educational plan consists of three main components that will focus on the research supervision of students, teaching, mentoring, and outreach to interface with the research components of the project. These components include the (i) development of a new graduate course on the interfacial phenomena of soft matter to be taught by the PI, (ii) mentoring of underrepresented undergraduate students in research, and (iii) dissemination of the project outcomes to the general public in the Akron area, where the minority constitutes 25% of the total population, by reliance on the connections established with local high school teachers through an educational electronic device development grant funded by NSF.