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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=708822
• 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.

拟议的研究计划是调查几种新的电动微流体现象，对于在医疗诊断和食品安全中应用实验室芯片设备的开发至关重要。拟议的研究计划将： （1）基于诱导的电荷电流动流而开发出一种新型的微泵。通过将一对小金属板嵌入微通道壁上，并通过将两个电势差插入靠近金属板的两个电极来实现这个新泵。应用的局部电场将在金属板上引起强烈的电渗水，从而泵送液体。这样的泵可以在微通道中的任何位置安装，并且不需要沿整个通道的大电势差（从而避免焦耳加热和对生物细胞的损害）。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，并将开发此类泵的工作原型。 （2）介电极化性对微通道中诱导电荷电流（ICEOF）的研究影响。到目前为止，由于简单性，几乎所有的ICEOF研究都限于完全极化（即金属）材料。但是，大多数参与微流体应用的材料都不完全极化。它们是介电材料，例如玻璃和聚合物。电介质的诱导表面电位对冰形至关重要。 这项研究的目的是找到诱导的电荷表面电位与施加的电场的相关性，固体及其周围液体的极化性。将进行广泛的数值模拟和实验验证。这项拟议的基础研究是该领域的第一项，将提供新的理解，并开发新的方法来控制介电颗粒的运动，并在微流体芯片中分离不同类型的介电颗粒。 （3）研究电诱导的Janus液滴（EIJD）的流场和运动。由于液滴的表面电荷是可移动的，因此由于吸引了施加的电场，因此可以将表面电荷拉到液滴表面的一侧。这将导致电诱导的Janus液滴（EIJD），这是一个液滴表面一侧的液滴；液滴表面的另一侧没有或很少的静电电荷。拟议的研究工作将研究（a）在电场的影响下，在液体界面的移动表面电荷重新分布； （b）围绕EIJD的流场和电场中EIJD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至少两种应用的EIJD运动：由EIJD控制的微流体阀以及不同的EIJD的分离。