Electrokinetic Microfluidics

动电微流控

• 批准号: RGPIN-2016-03622
• 负责人: Li, Dongqing
• 金额: $ 3.35万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=689264
• 关键词: Electrokinetic; Microfluidics

The proposed research program is to investigate several new electrokinetic microfluidic phenomena critical to the development of lab-on-a-chip devices for applications in medical diagnosis and food safety. The proposed research program will:****(1) Develop a novel micro-pump based on induced charge electroosmotic flow. This new pump is realized by embedding a pair of small metal plates on microchannel walls, and applying a small electrical potential difference via two electrodes placed close to the metal plates. The applied local electrical field will induce a strong electroosmotic flow over the metal plates and hence pump the liquid. Such a pump can be installed at any position in a microchannel, and does not require large electrical potential difference along the whole channel (thus avoiding Joule heating and damage to biological cells). Extensive theoretical and experimental studies will be carried out to examine and verify the proposed method, and working prototypes of such pumps will be developed.****(2) Study effects of dielectric polarizability on induced charge electroosmotic flow (ICEOF) in microchannels. So far, almost all studies of ICEOF are limited to fully polarizable (i.e., metal) materials due to simplicity. However, most materials involved in microfluidic applications are not fully polarizable; they are dielectric materials such as glass and polymers. The induced surface potential of dielectrics is critical to the ICEOF. The objective of this research is to find the correlation of the induced charge surface potential to the applied electrical field, the polarizability of the solid and its surrounding liquid. Extensive numerical simulations and experimental verifications will be conducted. This proposed fundamental research is the first in this field, will provide new understanding and develop new methods to control the motion of dielectric particles and to separate different types of dielectric particles in microfluidic chips.****(3) Study the flow field and motion of electrically induced Janus droplets (EIJD). As the surface charges of the droplet are mobile, the surface charges can be pulled to one side of the droplet surface due to the attraction to the applied electrical field. This will result in an electrically induced Janus droplet (EIJD), a droplet with electrostatic charges on one side of the droplet surface; the other side of the droplet surface has no or little electrostatic charges. The proposed research work will study (a) the redistribution of mobile surface charges of liquid-fluid interfaces under the influence of electrical field; (b) the flow field around an EIJD and the motion of EIJD in an electric field. With the fundamental understandings developed from this study, we will further study how to control of EIJD motion for at least two applications: a microfluidic valve controlled by EIJD, and separation of different EIJDs.***

拟议的研究计划是研究几种新的电动微流体现象，这些现象对开发用于医疗诊断和食品安全的芯片实验室设备至关重要。本论文的主要研究内容为：（1）开发一种基于感应电荷电渗流的新型微泵。这种新泵是通过在微通道壁上嵌入一对小金属板，并通过靠近金属板放置的两个电极施加小电势差来实现的。所施加的局部电场将在金属板上引起强的电渗流，从而泵送液体。这种泵可以安装在微通道中的任何位置，并且不需要沿整个通道沿着的大电势差（从而避免焦耳加热和对生物细胞的损伤）。将进行广泛的理论和实验研究，以检查和验证所提出的方法，并将开发这种泵的工作原型。(2)研究了介质极化率对微通道内诱导电荷电渗流的影响。到目前为止，几乎所有的ICs研究都局限于完全极化（即，金属）材料。然而，微流体应用中涉及的大多数材料不是完全可极化的;它们是介电材料，如玻璃和聚合物。表面诱导电位是影响离子导电的关键因素。 本研究的目的是找出感应电荷表面电位与外加电场、固体及其周围液体的极化率的相关性。将进行广泛的数值模拟和实验验证。这项基础研究是该领域的第一项研究，将为控制介电颗粒的运动和分离微流控芯片中不同类型的介电颗粒提供新的理解和开发新的方法。(3)研究了电诱导Janus液滴的流场和运动规律。由于液滴的表面电荷是移动的，因此由于施加的电场的吸引力，表面电荷可以被拉到液滴表面的一侧。这将导致电诱导Janus液滴（EIJD），液滴表面的一侧上具有静电荷的液滴;液滴表面的另一侧没有或几乎没有静电荷。拟开展的研究工作将研究（a）电场影响下液-液界面移动的表面电荷的重新分布;（B）EIJD周围的流场以及EIJD在电场中的运动。 通过这项研究的基本理解，我们将进一步研究如何控制EIJD运动至少两个应用：由EIJD控制的微流体阀，以及不同EIJD的分离。