Collaborative Research: FRG: Understanding and Controlling Active Fluids through Modeling, Simulation, and Experiment

软活性材料是颗粒、细胞或分子的集合，它们能够将来自其环境的化学能转化为运动和机械应力。例子包括游泳微生物、细胞提取物、生物聚合物和分子马达，以及大量旨在模拟生物系统的合成颗粒。这些主动系统在过去十年中在从工程到物理到应用数学的许多学科中产生了相当大的兴奋，表现出与传统被动材料根本不同的行为，并且它们的理解才刚刚开始阐明生物学中的长期问题并提出新的工程设备。该研究项目旨在使用实验，建模和模拟，以进一步提高对各种活性材料的理解。本项目的目的是通过建模、数学分析、数值模拟和实验相结合的方法，探索原型活性流体在其微观结构成分与障碍物、墙壁以及彼此相互作用时的动力学。计算和粗粒度模型将探索微泳者的相互作用，单独和集体，与边界和障碍。将制造微流体环境，以探索边界和障碍物如何影响和控制主动颗粒传输，并将使用形状优化工具来指导设计。将制造专门的粒子来阐明活性物质的不同方面。通过考虑粒子尺度活动和系统尺度限制的修改，将探索新类型的活性物质。这些研究将包括最近合成的活性流体的详细和粗粒度的计算模型，其中浸没的微管通过马达蛋白质交联和拉动相互作用，以及一种新的活性物质系统，其中颗粒活性耦合到界面力以驱动大规模流动。

Soft active materials are collections of particles, cells, or molecules that are capable of converting chemical energy from their environment into motion and mechanical stresses. Examples include swimming microorganisms, cellular extracts, biological polymers, and molecular motors, as well as a wealth of synthetic particles designed to mimic biological systems. These active systems, which have generated considerable excitement over the last decade in many disciplines from engineering to physics to applied mathematics, evince behaviors that are fundamentally different from traditional passive materials, and their understanding is just beginning to illuminate long-standing problems in biology and to suggest new engineering devices. This research project aims to use experiments, modeling, and simulations, to further enhance understanding of a variety of active materials. The project will also involve training through research involvement of postdoctoral researchers, graduate students, and undergraduates.The aim of this project is to use a combination of modeling, mathematical analysis, numerical simulations, and experiments to explore the dynamics of archetypal active fluids as their microstructural components interact with obstacles, walls, and each other. Computational and coarse-grained models will explore the interaction of microswimmers, individually and collectively, with boundaries and obstacles. Microfluidic environments will be fabricated to explore how active particle transport is affected and controlled by boundaries and obstacles, and tools of shape optimization will be used to guide the design. Specialized particles will be fabricated to elucidate different aspects of active matter. New types of active matter will be explored, both by considering modifications in particle-scale activity and system-scale confinement. These investigations will include detailed and coarse-grained computational models of recently synthesized active fluids in which immersed microtubules interact through motor-protein cross-linking and pulling, as well as a new active matter system in which particle activity couples to interfacial forces to drive large-scale flows.