The Pressure of Active Matter

活性物质的压力

• 批准号: 1437570
• 负责人: John Brady
• 金额: $ 30万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1437570&HistoricalAwards=false
• 关键词: Pressure; Active; Matter

CBET 1437570Suspensions containing particles that can propel themselves through a liquid are interesting examples of a class of materials called active matter. The self-propelled particles, which are sometimes thought of as swimmers, can contribute to the properties of the suspension as a whole. This project will explore a novel concept called the swim pressure that can help characterize the state of such a suspension. The swim pressure is similar to the usual pressure that molecules in a gas exert on the walls of a container, but in this case the pressure is exerted by self-propelled particles that could be microorganisms, chemically reactive particles, or micro-motors moving through liquid. Preliminary data suggest that the swim pressure and its dependence on particle concentration can be used to predict changes in the suspension, including phase changes, deformation and motion, that cannot be predicted by other theories for active matter. The project will investigate the swim pressure and its utility in predicting suspension behavior by carrying out a series of numerical simulations. The results will be useful to scientists and engineers who process active matter suspensions in pharmaceutical, medicinal, food and similar industries.The micromechanical origin of spontaneous self-assembly in suspensions of self-propelled particles will be investigated by focusing on the swim pressure exerted by the particles. Numerical simulations based on Accelerated Stokesian Dynamics and other methods will be used to determine the variation of swim pressure with particle concentration, activity, etc., which can be used to formulate a nonequilibrium equation of state and pressure-volume phase diagrams for the suspension. Hydrodynamic interactions among the particles will be included in the computations. The swim pressure will then be correlated with detailed motions of the active particles that can lead to spontaneous formation of clusters, aggregates and other patterns, as well as the overall deformation and motion of the suspension.

CBET 1437570 含有可自行穿过液体的颗粒的悬浮液是一类称为活性物质的材料的有趣例子。 自驱动颗粒有时被认为是游泳者，可以对悬浮液的整体性能做出贡献。 该项目将探索一种称为游泳压力的新概念，它可以帮助表征这种悬架的状态。游泳压力类似于气体中的分子施加在容器壁上的通常压力，但在这种情况下，压力是由自驱动颗粒施加的，这些颗粒可以是微生物、化学反应颗粒或移动通过的微型电机。液体。初步数据表明，游泳压力及其对粒子浓度的依赖性可用于预测悬浮液的变化，包括相变、变形和运动，这是其他活性物质理论无法预测的。 该项目将通过进行一系列数值模拟来研究游泳压力及其在预测悬挂行为中的效用。研究结果将对在制药、医疗、食品和类似行业中处理活性物质悬浮液的科学家和工程师有用。将通过关注自驱动颗粒悬浮液施加的游动压力来研究自驱动颗粒悬浮液中自发自组装的微机械起源。颗粒。 采用基于加速斯托克斯动力学等方法的数值模拟，确定游动压力随颗粒浓度、活度等的变化，从而建立悬浮液的非平衡状态方程和压力-体积相图。 粒子之间的流体动力学相互作用将包含在计算中。 然后，游泳压力将与活性颗粒的详细运动相关联，这些运动可以导致簇、聚集体和其他模式的自发形成，以及悬浮液的整体变形和运动。