Electrohydrodynamics of particle-covered drops

这个项目将探索有小颗粒吸附在其界面上的液滴的行为。当液滴被放置在电场中时，界面上的粒子可以组装成各种有趣的结构，包括围绕液滴旋转和波动的粒子带。这些结构在某些情况下会变得不稳定，导致弯曲或起皱。研究人员将通过实验绘制出由流体、粒子和电场特性组成的结构。然后，他们将利用实验结果建立一个模型来预测观察到的不稳定性。当颗粒完全覆盖液滴的界面时，界面就像一个弹性固体。水滴形状在流动中的变形方式将被用来推断界面的力学特性。该项目的信息将有助于科学家和工程师设计和加工新型胶体产品，如具有可响应当地环境的界面的液滴。漏电介质液滴中的电流体动力学流动可以用来构造和操纵液滴表面的胶体颗粒。该项目将建立放置在电场中的液滴上的粒子组装机制，将粒子结构和液滴行为联系起来，以控制电场强度、粒子和流体性质等参数。对低颗粒覆盖率的液滴进行实验研究，构建颗粒结构相图，测量颗粒结构对液滴流动变形的影响。对于高表面覆盖率滴，滴变形将用于确定界面的弹性性能。漏电介质模型和小变形理论将用于将液滴变形与界面弹性特性联系起来，并预测液滴旋转的电场阈值作为表面电导率的函数。该研究成果将导致具有多功能和可控表面覆盖的新型胶体包覆滴的工程化。

CBET 1437545This project will explore the behavior of liquid drops that have small particles adsorbed on their interfaces. When the drops are placed in an electric field, the particles on the interface can assemble into a variety of interesting structures, including particle belts that rotate and undulate around the drop. These structures can become unstable in some conditions, leading to bucking or wrinkling. The investigators will experimentally map out the structures that form as a function of fluid, particle, and electric field properties. Then, they will use the experimental results to develop a model to predict the observed instabilities. When the particles completely cover the interface of the drop, the interface resembles an elastic solid. The way the drop shape deforms in flow will be used to deduce the mechanical characteristics of the interface. The information from this project will be useful to scientists and engineers to design and process novel colloidal products such as drops with interfaces that can respond to their local environment.Electrohydrodynamic flow in leaky-dielectric liquid drops can be used to structure and manipulate colloidal particles at the drop surface. This project will establish the mechanisms of particle assembly on a drop placed in an electric field to relate particle architectures and drop behavior to control parameters such as field strength, particle and fluid properties. Experimental studies will be carried out for drops with low particle coverage to construct a phase diagram of particle structures and the influence of particle structure on drop deformation in flow will be measured. For high surface coverage drops, drop deformation will be used to determine elastic properties of the interface. A leaky dielectric model and small deformation theory will be used to relate drop deformation and elastic properties of the interface and to predict the electric field threshold for rotation of the drops as a function of surface conductivity. The research outcomes will lead to the engineering of novel colloidal-coated drops with versatile and controllable surface coverage.