Active emulsions: Magneto-capillary dynamics of particles at curved interfaces

活性乳液：弯曲界面处颗粒的磁毛细管动力学

• 批准号: 1935228
• 负责人: Kyle Bishop
• 金额: $ 36.84万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-01 至 2023-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1935228&HistoricalAwards=false
• 关键词: Active; emulsions; Magneto; capillary; dynamics

Oil and water don’t mix; however, by stabilizing the interface between them, small droplets of one can be dispersed in the other. These so-called emulsions are commonly found in foods, cosmetics, and pharmaceuticals where mixtures of oil-loving and water-loving molecules must work together to function properly. Surface-active molecules and particles - termed surfactants - adsorb at oil-water interfaces to stabilize emulsions and prevent unmixing. This project aims to create magnet surfactants that use external magnetic fields to power dynamic functions such as mixing and propulsion at the level of individual emulsion droplets. The project will investigate the magnetically driven motions of particles adsorbed at curved interfaces and their use in pumping fluids at the micron-scale. The resulting active emulsions are potentially important for accelerating and/or controlling the rates of drug delivery or chemical reactions within complex fluids. In addition to research training for graduate and undergraduate students, the project will provide educational outreach to middle and high school students from diverse backgrounds. In collaboration with the Inside Engineering initiative, the researchers will develop and implement a laboratory visit curriculum for students from nearby schools in Manhattan and the Bronx. Through hands-on demonstrations and active learning strategies, the program aims to get students excited about the processes of scientific inquiry and engineering design.Rapid particle motions in uniform fields are made possible by coupling magnetic torques to capillary forces at curved interfaces. Building on recent demonstrations of these magneto-capillary dynamics, the project will investigate how time-varying magnetic fields can drive complex particle motions and interfacial flows within and around liquid droplets. The project aims (1) to understand how the waveform of the driving field and the properties of the magnetic particles direct their dynamic motions on curved interfaces; (2) to quantify the transient fluid flows within and around emulsion droplets induced by particle motions; and (3) to identify specific particle types and driving protocols optimized for desired functions such as enhancing mass transfer and propelling droplet motions. These aims will be achieved through a combination of experiments on particle/emulsion systems and modeling of magneto-capillary particle dynamics and fluid flows. The project will examine how these field induced flows can be harnessed for enhancing mass transfer and for propelling drop motions. In contrast to bulk processing of macroscopic emulsions, distributed actuation within active emulsions will enable new strategies for engineering reaction kinetics, mass transport, and separations within multiphase fluids. In pursuit of these functions, automated tools for Bayesian inference, experimental design, and optimization will be developed and deployed to enable the efficient exploration of possible driving fields.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

油和水不相溶；然而，通过稳定它们之间的界面，一个的小液滴可以分散在另一个中。这些所谓的乳液常见于食品、化妆品和药品中，其中亲油分子和亲水分子的混合物必须共同作用才能正常发挥作用。表面活性分子和颗粒（称为表面活性剂）吸附在油水界面上，以稳定乳液并防止分离。该项目旨在创建磁性表面活性剂，利用外部磁场来驱动动态功能，例如在单个乳液液滴水平上的混合和推进。该项目将研究吸附在弯曲界面上的颗粒的磁驱动运动及其在微米级泵送流体中的用途。所得的活性乳液对于加速和/或控制复杂流体内的药物输送或化学反应的速率具有潜在的重要意义。除了为研究生和本科生提供研究培训外，该项目还将为来自不同背景的初高中生提供教育推广。研究人员将与内部工程计划合作，为曼哈顿和布朗克斯附近学校的学生开发和实施实验室参观课程。通过动手演示和主动学习策略，该项目旨在让学生对科学探究和工程设计的过程感到兴奋。通过将磁扭矩与弯曲界面处的毛细管力耦合，可以实现均匀场中的快速粒子运动。基于最近这些磁毛细管动力学的演示，该项目将研究时变磁场如何驱动复杂的粒子运动以及液滴内部和周围的界面流。该项目的目标是（1）了解驱动场的波形和磁性粒子的特性如何引导它们在弯曲界面上的动态运动； (2) 量化由粒子运动引起的乳液液滴内部和周围的瞬态流体流动； (3) 识别特定的颗粒类型和针对所需功能（例如增强传质和推动液滴运动）进行优化的驱动方案。这些目标将通过颗粒/乳液系统实验与磁毛细管颗粒动力学和流体流动建模相结合来实现。该项目将研究如何利用这些场诱导流来增强传质和推动液滴运动。与宏观乳液的批量处理相比，活性乳液内的分布式驱动将为多相流体内的工程反应动力学、质量传递和分离提供新的策略。为了实现这些功能，将开发和部署用于贝叶斯推理、实验设计和优化的自动化工具，以实现对可能的驾驶领域的有效探索。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Magneto-capillary particle dynamics at curved interfaces: inference and criticism of dynamical models

• DOI: 10.1039/d3sm01256e
• 发表时间: 2023-11-09
• 期刊: SOFT MATTER
• 影响因子: 3.4
• 作者: Livitz，Dimitri;Dhatt-Gauthier，Kiran;Bishop，Kyle J. M.
• 通讯作者: Bishop，Kyle J. M.