Advanced Algorithms for Colloids with Induced Many-Body Interactions

非技术总结该奖项支持计算和理论研究，重点是开发新的方法，利用计算机模拟来了解悬浮在另一种介质中的胶体颗粒的自组装，胶体颗粒是指尺寸在1到1000纳米之间的物体。它们可以作为构建块来创造可以通过外部电场和磁场进行重构和调谐的新材料，这已成为当前材料科学和工程的重要焦点。这类材料的应用范围很广，但人们对构成这种材料的各个构件如何应对随时间变化的电场的反应知之甚少，例如由交流电驱动的电磁铁产生的磁场。PI和他的研究团队正在开发新的计算方法，使以前所未有的精度预测和理解这些性质成为可能，为设计响应性材料开辟了道路。同样的算法也可以用来理解和改进微流控设备，在微流控设备中，微量的流体被操纵，例如用于分析目的。该项目开发的计算方法将被集成到材料和其他研究社区广泛使用的计算机模拟包中。PI将继续维护一个维基，该维基提供在他的小组中开发的计算工具，这已经成为更广泛的计算研究社区的资源。技术总结该奖项支持专注于加速算法的开发和应用的计算和理论研究，这些加速算法解释了由电和磁极化引起的诱导多体相互作用。这些方法将被用来探索和理解各向异性胶体在外场中的新的动力学行为，并设计用于靶向自组装的构建块。胶体颗粒在悬浮液中的动力学和自组装引起了广泛的兴趣，因为它们可以创造出具有新结构的材料。直到最近才有了算法，使模拟这些现象成为可能，同时考虑到完全解析的表面极化。PI现在将利用这种方法来探索和理解各向异性胶体在外场中的行为，在外场中，双电层被扭曲，引起诱导相互作用，甚至导致集体动力学的推进。此外，算法将扩展到整体极化率，这一现象到目前为止还几乎没有通过计算来探索，以及一种混合方法，与目前可能的方法相比，这种方法将使重要的介电模型系统的模拟速度提高两个数量级。软材料的计算机模拟现在通常考虑远程静电相互作用。近年来，介电失配的作用越来越受到人们的关注，介电失配在自然界中普遍存在，但由于其计算复杂性而传统上被忽视。在之前NSF的支持下，PI开发了一个研究程序，提供了一种实用的边界元方法，能够处理移动的电介质对象。目前的项目应用这种方法来理解活性物质模型系统中的推进机制和微流控装置中的电渗流行为。此外，块状介质的等效算法的开发将使材料行为的研究成为可能，因为缺乏适当的计算技术。这项研究是及时的，因为控制胶体相互作用是可重构材料开发的重点。计算方法和资源现在能够为实验提供直接指导。这里提出的进展将显著扩展现有的能力，并阐明动态集体现象以及诱导相互作用驱动的自组装。该项目开发的计算方法将集成到材料和其他研究团体广泛使用的计算机模拟程序包中。PI将继续维护一个维基，该维基提供在他的团队中开发的计算工具，该工具已成为更广泛的计算研究社区的资源。

NONTECHNICAL SUMMARYThis award supports computational and theoretical research with a focus on developing new ways to use computer simulation to understand self-assembly of colloidal particles, objects with sizes in the range 1 to 1000 nanometers, suspended in another medium. They can be used as building blocks to create new materials that can be reconfigured and tuned by means of external electric and magnetic fields, which has become an important focal point of current materials science and engineering. Such materials find a wide range of applications, but it is poorly understood how the individual building blocks making up the material respond to fields that vary over time, such as those generated by electromagnets powered by alternating currents. The PI and his research team are developing novel computational methods that make it possible to predict and understand such properties with unprecedented accuracy, opening the way to designing responsive materials. The same algorithms also can be employed to understand and improve microfluidic devices, in which minute amounts of fluids are manipulated, for example for analytic purposes.Computational methods developed by this project will be integrated into computer simulation packages widely used by the materials and other research communities. The PI will continue to maintain a Wiki that provides computational tools developed in his group which has become a resource to the broader computational research community.TECHNICAL SUMMARYThis award supports computational and theoretical research focused on the development and application of accelerated algorithms that account for induced many-body interactions that arise from electric and magnetic polarizability. These methods will be used to explore and understand new dynamical behavior of anisotropic colloids in external fields, and to design building blocks for targeted self-assembly. The dynamics and self-assembly of colloidal particles in suspension are of widespread interest, as they allow the creation of materials with novel structures. Only recently have algorithms become available that make it possible to simulate these phenomena while taking into account fully resolved surface polarization. The PI will now exploit this approach to explore and understand the behavior of anisotropic colloids in external fields, where the electric double layer is distorted, giving rise to induced interactions or even propulsion that results in collective dynamics. Moreover, the algorithms will be extended to bulk polarizability, a phenomenon that until now has barely been explored computationally, and to a hybrid method that will accelerate the simulation of important classes of dielectric model systems by two orders of magnitude compared to what is currently possible.Computer simulations of soft materials now routinely take into account long-range electrostatic interactions. In recent years increasing attention has been devoted to the role of dielectric mismatch ubiquitous in nature but traditionally ignored owing to its computational complexity. With prior NSF support, the PI has developed a research program that has delivered a practically usable boundary-element method capable of dealing with mobile dielectric objects. The current project applies this method to understand the propulsion mechanism in model systems of active matter and the behavior of electro-osmotic flow in microfluidic devices. Moreover, the development of an equivalent algorithm for bulk dielectrics will enable the study of materials behavior that has been virtually unexplored for want of appropriate computational techniques.This research is timely because control over colloidal interactions is a focal point in the development of reconfigurable materials. Computational methods and resources are now able to provide direct guidance to experiments. The advances proposed here will significantly extend existing capabilities and elucidate dynamic collective phenomena as well as self-assembly driven by induced interactions.Computational methods developed by this project will be integrated into computer simulation packages widely used by the materials and other research communities. The PI will continue to maintain a Wiki that provides computational tools developed in his group which has become a resource to the broader computational research community.