Exploring the contributions of multiple physical forces towards the self-assembly of complex macroions in solution

许多生物分子，如蛋白质和DNA，都含有许多同类型的带电(离子)基团。在这些分子中观察到的一个现象是，它们在水中可以相互缔合，尽管正电荷基团排斥其他正电荷基团(或负电荷排斥负电荷)。阿克伦大学的刘天波教授设计并研究了复杂的带电分子，这种分子是大的，可溶于水，即使它们携带相同的电荷(正电荷或负电荷)，它们也会相互吸引。通过研究不同类型的分子间力在溶液中是如何相互协作和竞争的，刘小组对这些离子如何相互吸引有了更好的理解。这些结论可望适用于许多其他溶液体系，并对理解生物溶液具有指导意义。该项目对包括物理化学、超分子化学、生物化学和材料科学在内的许多科学学科做出了重要贡献。此外，能够操纵不同分子间作用力的强度和影响将使设计用于纳米技术或生物技术的新型自组装结构成为可能。该项目为高中生、本科生和研究生提供研究培训，为他们在STEM领域的进一步教育或职业生涯做好准备。在简单的离子溶液(如氯化钠)和体积较大的胶体颗粒悬浮液之间，存在一个大离子区域-纳米级可溶离子。在高分子、超分子和纳米化学计划的支持下，刘教授将他的研究项目从以极性溶剂中的静电相互作用为主的纯亲水大离子扩展到具有其他作用力(疏水、阳离子-pi、pi-pi等)的更复杂的大离子。也是在场的。在这种大离子溶液中，各种分子间力的合作和竞争有望显示出丰富的组装现象。这个项目有三个主要目标。首先，该项目旨在了解带有有机基团的大离子的官能化对此类离子在极性溶剂中的性质的影响。其次，设计、合成了具有可聚合疏水基团的哑铃形大离子，并将其组装成单层中空、球形的黑莓状结构。连接物的聚合有望产生稳定的、多孔的纳米容器。最后，考察了芳香族基团对大离子周围反离子分布的影响以及它是如何导致各种可控组装结构的。这一奖项反映了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。

Many biological molecules, such as proteins and DNA, contain many charged (ionic) groups of the same kind. A phenomenon observed in these molecules is that they can associate with each other in water despite the fact that positively-charge groups repel other positively-charged groups (or negative charges repel negative charges). Professor Tianbo Liu of the University of Akron designs and studies complex charged molecules that are large and water-soluble, and that attract each other even when they carry the same charge (positive or negative). Through an investigation of how different kinds of inter-molecular forces cooperate and compete with each other in solution, the Liu group gains a better understanding of how such ions attract one another. The conclusions are expected to be applicable to many other solution systems, and instructive for understanding biological solutions. The project contributes fundamentally to many science disciplines including physical chemistry, supramolecular chemistry, biochemistry, and materials sciences. In addition, the ability to manipulate the strengths and the effects of different inter-molecular forces would enable the design of novel self-assembled structures for applications in nanotechnology or biotechnology. This project provides research training to high school, undergraduate and graduate students, preparing them for further education or careers in STEM fields.Between simple ionic solutions (e.g., sodium chloride) and the suspensions of bulky colloidal particles, there exists a region of macroions - nanoscaled soluble ions. Supported by the Macromolecular, Supramolecular and Nanochemistry Program, Professor Liu expands his research project from the study of purely hydrophilic macroions, dominated by electrostatic interactions in polar solvents, to more complicated macroions with other forces (hydrophobic, cation-pi, pi-pi, etc.) also being present. The cooperation and competition of various intermolecular forces in such macroionic solutions are expected to demonstrate rich assembly phenomena. There are three main objectives in this project. First, the project aims to understand the effect of functionalization of macroions with organic groups on the properties of such ions in polar solvents. Secondly, dumbbell-shaped macroions with polymerizable hydrophobic linkers are designed, synthesized, then assembled into single-layered hollow, spherical "blackberry-like" structures. Polymerization of the linkers is expected to create stable, porous nanocontainers. Finally, the effects of aromatic groups on the counterion distribution around the macroions and how it leads to various controllable assembly structures are examined.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.