UNS: Modeling and Experimental Studies of the Interactions of 2D Materials with Solvents and Surfactants: Exfoliation, Self-Assembly of Composites, and Wetting.

2D材料与溶剂和表面活性剂相互作用的建模和实验研究：剥离，复合材料的自组装和WettingBlankschtein，Daniel二维（2D）材料，如石墨烯，六方氮化硼（h-BN）和二硫化钼（MoS 2），由于其独特的和奇异的电子，光学，和机械性能。然而，由于缺乏具有成本效益的大规模生产技术，基于这些材料的技术的商业化受到阻碍。一种潜在的廉价、可扩展的制造路线包括将相应的块状材料（例如，在石墨烯的情况下为石墨）浸入液体中并快速搅拌整个系统。这就像食品加工机切割蔬菜一样，将单个单层从散装材料中分离出来。这种“剥离”过程的效率取决于溶剂分子和材料之间的相互作用。因此，为了确定给定材料的最佳剥离溶剂，在分子尺度上理解这些相互作用是必不可少的。为了阐明这些相互作用，PI建议使用计算机模拟来研究几种有前途的2D材料片周围的各种溶剂分子的行为。从这些计算机模拟中获得的见解也可以帮助设计溶剂，鼓励自发形成几种2D材料的混合堆叠（例如在MoS 2顶部的h-BN顶部的石墨烯），这些材料可能具有非常特殊的性质和应用。PI试图理解和模拟溶剂/表面活性剂分子与溶液相中各种2D材料之间的分子相互作用。这将能够预测各种新的2D材料及其复合材料的胶体分散体的热力学和动力学稳定性，这对于调节电子和光电应用中的带隙变得越来越重要。为此，经典的分子动力学（MD）模拟方法保留了系统的原子细节，而不牺牲所涉及的长度和时间尺度。虽然目前已有几种很好的液体和材料模型，但用于模拟液体和材料之间相互作用力的努力要少得多。为此，PI建议开发力场来模拟涉及2D材料和液体介质的界面现象。所开发的模型的预测将与实验进行比较，从而允许跨不同的界面系统的参数的可转移性。 从这种建模工作中获得的见解将能够精确控制2D材料悬浮液中层的尺寸，形状，数量分布和堆叠顺序，以获得所需的电子和光学特性。此外，力场将用于预测润湿性能，这对这些材料在膜、微流体设备、电池电极和其他电化学设备中的使用至关重要。所取得的建模和实验进展将被纳入麻省理工学院的课程和研讨会，这将使更多的科学观众了解2D材料在液相中分散和稳定的基本原理，二维材料的润湿行为，以及在分子水平上模拟这些现象。参与拟议研究的学生，在研究生和本科生水平，将获得智力和专业从这里提出的综合建模/实验研究。

Modeling and Experimental Studies of the Interactions of 2D Materials with Solvents and Surfactants: Exfoliation, Self-Assembly of Composites, and WettingBlankschtein, DanielTwo-dimensional (2D) materials such as graphene, hexagonal boron nitride (h-BN), and molybdenum disulfide (MoS2) are poised to usher in the next generation of digital electronics, sensors, and membranes due to their unique and exotic electronic, optical, and mechanical properties. However, the commercialization of technologies based on these materials is impeded by the absence of cost-effective, large-scale production techniques. One potentially inexpensive, scalable manufacturing route consists of immersing the corresponding bulk material (for example, graphite in the case of graphene) in a liquid and rapidly stirring the entire system. This separates individual monolayers from the bulk material in the same way that a food processor slices vegetables. The efficiency of this "exfoliation" process depends on the interactions between the solvent molecules and the material. Consequently, understanding these interactions at a molecular scale is essential in order to determine the optimal exfoliating solvent for a given material. To shed light on these interactions, the PIs propose to use computer simulations to study the behavior of a variety of solvent molecules around sheets of several promising 2D materials. The insights obtained from these computer simulations can also assist in designing solvents that encourage the spontaneous formation of mixed stacks of several 2D materials (such as graphene on top of h-BN on top of MoS2) that could have very special properties and applications. The PIs seek to understand and model the molecular interactions operating between solvent / surfactant molecules and various 2D materials in a solution phase. This will enable the prediction of the thermodynamic and kinetic stability of colloidal dispersions of various new 2D materials and their composites, which are becoming increasingly important for modulating the band gap in electronic and optoelectronic applications. For this purpose, a classical molecular dynamics (MD) simulation approach retains atomic detail of the system, without sacrificing on the length and time scales involved. Although several good models for liquids and materials are currently available, much less effort has been devoted to modeling the interaction forces between liquids and materials. To this end, the PIs propose to develop force fields to model the interfacial phenomena involving 2D materials and liquid media. The predictions made by the models developed will be compared with experiments, thereby allowing transferability of parameters across different interfacial systems. The insights obtained from such modeling efforts will enable the precise control of the size, shape, number distributions, and stacking order of layers in suspensions of 2D materials to obtain desired electronic and optical properties. Furthermore, the force fields will be used to predict wetting properties, which are critical to the use of these materials in membranes, microfluidic devices, battery electrodes, and other electrochemical devices.The modeling and experimental advances made will be incorporated into courses and workshops at MIT that will expose a larger scientific audience to the fundamentals of 2D material dispersion and stabilization in liquid phases, wetting behavior of 2D materials, as well as to modeling these phenomena at the molecular level. The students involved in the proposed research, at both the graduate and undergraduate levels, will gain intellectually and professionally from the integrated modeling / experimental research proposed here.