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 1437570Suspensions含有可以通过液体推动自己的颗粒的CBET，是一类称为活性物质的材料的有趣例子。 有时被认为是游泳者的自属性颗粒可以促进整个悬架的特性。 该项目将探索一个名为“游泳压力”的新颖概念，该概念可以帮助表征这种悬架的状态。游泳压力类似于在容器壁上施加的气体中的分子的通常压力，但是在这种情况下，压力是由可能是微生物，化学反应性颗粒或微电机通过液体移动的自propelled颗粒所施加的。初步数据表明，游泳压力及其对颗粒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，而其他理论无法预测活性物质。 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浮行为方面的效用。结果对于处理药物，药用，食品和类似行业的主动物质悬浮液的科学家和工程师将很有用。自发自我组装的微机械起源将通过专注于颗粒施加的游泳压力来研究自propelled颗粒的悬浮液。 基于加速的Stokesian动力学和其他方法的数值模拟将用于确定游泳压力与颗粒浓度，活性等的变化，可用于制定悬浮液的状态和压力量相图的非平衡方程。 颗粒之间的流体动力相互作用将包括在计算中。 然后，游泳压力将与活动颗粒的详细运动相关，这些动作可能导致簇，聚集体和其他模式的自发形成，以及悬架的总体变形和运动。