Elucidating the Unique Self-Assembly Behavior of Macroions in Solution From Molecular Level Modeling

自组装是单个分子构建块之间的特定力导致有序结构自发形成的过程。从雪花的结晶到核糖体和病毒，分子自组装在自然界中无处不在。分子自组装已经成为化学合成中的一种新方法，为一系列具有科学意义和技术重要性的材料提供了途径。在化学学部大分子、超分子和纳米化学项目的支持下，阿克伦大学的Mesfin Tsige教授正在使用计算机模拟来研究溶液中带有多个电荷的大分子（称为宏离子）的自组装行为。计算机模拟跟踪了数万到数十万个珠子的运动，每个珠子代表几个原子，因为它们自发地形成了大型复杂结构。从这些模拟中，Tsige教授和他的团队对宏离子的自组装有了基本的了解，这在理论和模拟中几乎是完全未知的。该项目涉及阿克伦大学的研究生和博士后，以及通过聚合物科学和聚合物工程学院nsf本科生研究经验（REU）网站的本科生，以及来自当地圣文森特-圣文森特大学的高中生。玛丽的学校。该项目通过提供难以或有时不可能从实验室测量中获得的信息来补充现有的实验研究。该项目的核心是开发一种通用的粗粒度计算机模拟模型，该模型专为大规模分子动力学模拟而设计。一个典型的模拟跟踪了25-50个宏离子被10 -20万个溶剂分子包围成大型“黑莓”结构的自组装过程，耗时超过5000万步。齐格教授和他的学生们正在利用计算机模型来阐明组装形成的机制，并了解电荷密度、电荷分布、宏离子大小和溶剂极性对自组装行为的影响。这种建模方法可以促进我们在广泛的宏离子溶液中对自组装的理解，这些宏离子溶液涵盖了化学、材料科学和生物学的各个领域。

Self-assembly is the process by which specific forces between individual molecular building blocks leads to the spontaneous formation of ordered structures. Molecular self-assembly is ubiquitous in nature from the crystallization of snowflakes to ribosomes and viruses. Molecular self-assembly has emerged as a new approach in chemical synthesis, providing routes to a range of materials that are both scientifically interesting and technologically important. With the support of the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Professor Mesfin Tsige of the University of Akron is using computer simulation to investigate the self-assembly behavior of very large molecules with multiple charges (called macroions) in solution. The computer simulation tracks the motion of tens of thousands to hundreds of thousands of beads, each representing a few atoms, as they spontaneously form large complex structures. From these simulations, Professor Tsige and his group are developing a fundamental understanding of the self-assembly of macroions that are almost completely uncharted by theory and simulation. The project involves graduate students and postdoctoral associates at the University of Akron, as well as undergraduate students through the NSF-Research Experiences for Undergraduates (REU) site at the College of Polymer Science and Polymer Engineering, and high school students from the local St. Vincent-St. Mary School. The project complements existing experimental studies by providing information that is difficult or sometimes impossible to get from laboratory measurements. Central to the project is the development of a versatile coarse-grained computer simulation model that is designed for large-scale molecular dynamic simulation. A typical simulation tracks the self-assembly of 25-50 macroions surrounded by 100,000-200,000 solvent molecules into large 'blackberry-like' structures over the course of over 50 million time steps. Together, Professor Tsige and his students are using the computer model to elucidate the mechanism of assembly formation and understand the effects of charge density, charge distribution, macroion size, and solvent polarity on self-assembly behavior. This modeling methodology may advance our understanding of self-assembly in a broad range of macroion solutions, which cover a variety of fields in Chemistry, Material Science, and Biology.