Microdynamics and Macroscopic Function of Active Colloidal Gels

活性胶体凝胶的微观动力学和宏观功能

• 批准号: 1702418
• 负责人: Michael Solomon
• 金额: $ 34.67万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1702418&HistoricalAwards=false
• 关键词: Microdynamics; Macroscopic; Function; Active; Colloidal

CBET - 1702418PI: Solomon, MichaelWhen a concentrated suspension of colloidal particles forms networks of particles, the result is a material called a soft colloidal gel. The elastic properties of colloidal gels can be tuned by changing the characteristics of the particles, which makes colloidal gels useful in many consumer products, agricultural applications, and pharmaceuticals. This award will support the development and characterization of colloidal gels that incorporate active particles into their structures. Active particles can generate their own propulsion under certain conditions. When active particles are embedded in a colloidal gel, the extent to which the properties of the gel can be varied and controlled is expanded, which could increase the use of colloidal gels in practice. The properties of the gels containing active particles will be investigated using a combination of microscopy and mechanical testing. Results of the research will be disseminated through an industry/academic workshop. In addition, the research will be used to create hands-on demonstrations for middle school girls participating in a summer school that introduces young students to engineering. This project will establish the relationship between the microdynamics of active colloids embedded in colloidal gels and their macroscopic functional properties of linear elasticity and non-linear yielding. These micro/macro relationships will be generated by investigating active colloids introduced into fractal cluster gels, a system whose structure, dynamics, elasticity, and yielding are well understood for the case of passive, Brownian colloids. Active platinum Janus particles driven by hydrogen peroxide decomposition, two-channel confocal microscopy, fractal cluster gel self-assembly, and macroscopic rheology with a novel, permeable fixture will be used to discover: (i) how microscopic activity affects the linear elastic modulus of gels; (ii) how internally-induced yielding presents macroscopically, and; (iii) how consolidation and disintegration of gels is produced by the external pressure of active colloids. The work will yield insight into how the unusual microdynamics of active systems determine their macroscopic rheological function.

当胶体颗粒的浓缩悬浮液形成颗粒网络时，结果是一种称为软胶体凝胶的材料。胶体凝胶的弹性特性可以通过改变颗粒的特性来调节，这使得胶体凝胶在许多消费品、农业应用和药品中都很有用。该奖项将支持将活性颗粒纳入其结构的胶体凝胶的开发和表征。活性粒子可以在一定条件下产生自己的推进力。当活性颗粒嵌入胶凝胶中时，凝胶的性质可以变化和控制的程度扩大，这可以增加胶凝胶在实践中的使用。含有活性颗粒的凝胶的性质将使用显微镜和机械测试相结合的方法进行研究。研究结果将通过一个工业/学术讲习班传播。此外，该研究还将用于为参加向年轻学生介绍工程的暑期学校的中学女生制作实际演示。本项目将建立嵌入胶体凝胶中的活性胶体的微观动力学与其线弹性和非线性屈服的宏观功能特性之间的关系。这些微观/宏观关系将通过研究引入分形团簇凝胶的活性胶体来产生，这种体系的结构、动力学、弹性和屈服对于被动的布朗胶体来说是很好的理解。过氧化氢分解驱动的活性铂Janus粒子、双通道共聚焦显微镜、分形簇凝胶自组装和具有新型可渗透固定装置的宏观流变学将用于发现：(i)微观活性如何影响凝胶的线弹性模量；（ii）内部诱导屈服的宏观表现；（iii）活性胶体的外部压力如何产生凝胶的固结和解体。这项工作将使我们深入了解活性系统不寻常的微动力学如何决定它们的宏观流变功能。

项目成果

Rheological implications of embedded active matter in colloidal gels

胶体凝胶中嵌入活性物质的流变学意义

• DOI: 10.1039/c9sm01496a
• 发表时间: 2019
• 期刊: Soft Matter
• 影响因子: 3.4
• 作者: Szakasits, Megan E.;Saud, Keara T.;Mao, Xiaoming;Solomon, Michael J.
• 通讯作者: Solomon, Michael J.

Yield stress behavior of colloidal gels with embedded active particles

嵌入活性颗粒的胶体凝胶的屈服应力行为

• DOI: 10.1122/8.0000163
• 发表时间: 2021
• 期刊: Journal of Rheology
• 影响因子: 3.3
• 作者: Saud, Keara T.;Ganesan, Mahesh;Solomon, Michael J.
• 通讯作者: Solomon, Michael J.