Collaborative Research: Concentration Polarization Induced Electrokinetic Flows around dielectric Surfaces

合作研究：聚光极化引起介电表面周围的动电流

• 批准号: 2127852
• 负责人: Hui Zhao
• 金额: $ 20.56万
• 依托单位: University of Nevada Las Vegas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-15 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2127852&HistoricalAwards=false
• 关键词: Collaborative; Research; Concentration; Polarization; Induced

Precise control flow in microfluidic systems has many applications in areas such as clinical diagnosis, drug discovery, detection of chemical and biological pathogen, immunoassays, rapid chemical analysis, biodefense, etc. Recent experiments have discovered a new type of fluid flow around charged dielectric surfaces under the action of electric fields. These flows are hypothesized to result from an effect known as concentration polarization around the dielectric surfaces. Such concentration polarization-induced flows can be readily controlled by tuning the properties of the dielectric structure and the fluid. This feature promises a versatile technique for microfluidic flow control, including pumping and mixing, as well as manipulation of particles. The principal aim of this project is to elucidate the mechanism of the concentration polarization-induced flow around dielectric surfaces. This project will also focus on broadening participation from women and underrepresented minority groups and provide them with a bridge toward research-related careers. It will provide education and hands-on training in microfluidics to undergraduate, graduate, and high school students.The goal of this project is to develop a comprehensive understanding of the various control parameters for the concentration polarization induced electrokinetic flow via a combined experimental and theoretical approach. Specifically, the flow velocity will be directly measured and compared with the theoretical prediction in terms of the electric field frequency, salt concentration, surface zeta potential, and dielectric permittivity. Furthermore, the broken symmetry of stationary dielectric posts and hence the asymmetric concentration polarization induced electrokinetic flow will be exploited for microfluidic pumping. Finally, the concentration polarization induced electrokinetic flow around dielectric particles will be demonstrated and exploited for particle manipulation. The proposed experiments can quantitatively verify the proposed theoretical predictions to deepen the fundamental understanding of this flow. All parameters needed for the mathematical model can be obtained accurately from the complementary experiments. Such a rigorous comparison between theory and experiment features the unique contribution of this proposed research to the field: it will not only provide crucial insights for revealing the underlying physics, but also provide the guidance to exploit concentration polarization induced electrokinetic flows for various microfluidic applications.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.

微流体系统中的精确控制流在临床诊断、药物发现、化学和生物病原体检测、免疫测定、快速化学分析、生物防御等领域有许多应用。最近的实验发现了一种围绕带电介电表面的新型流体流动在电场的作用下。假设这些流动是由介电表面周围的浓差极化效应引起的。通过调节介电结构和流体的特性可以容易地控制这种浓差极化引起的流动。这一功能为微流体控制提供了一种多功能技术，包括泵送和混合，以及颗粒的操纵。该项目的主要目的是阐明介电表面周围浓差极化引起的流动的机制。该项目还将侧重于扩大女性和代表性不足的少数群体的参与，并为他们提供通向研究相关职业的桥梁。它将为本科生、研究生和高中生提供微流体学的教育和实践培训。该项目的目标是通过实验和理论相结合，全面了解浓差极化诱导动电流的各种控制参数。方法。具体来说，将直接测量流速，并在电场频率、盐浓度、表面zeta电位和介电常数方面与理论预测进行比较。此外，静止介电柱的对称性破缺以及由此引起的不对称浓差极化引起的动电流将被用于微流体泵送。最后，将演示介电粒子周围的浓差极化引起的动电流，并将其用于粒子操纵。所提出的实验可以定量验证所提出的理论预测，以加深对此流程的基本理解。数学模型所需的所有参数都可以从补充实验中准确获得。理论与实验之间的这种严格比较体现了这项研究对该领域的独特贡献：它不仅为揭示基础物理提供了重要的见解，而且还为各种微流体应用中利用浓差极化引起的动电流提供了指导。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

Interplay of induced charge electroosmosis and electrothermal flow in insulator-based dielectrophoresis

基于绝缘体的介电泳中感应电荷电渗和电热流的相互作用

• DOI: 10.1103/physrevfluids.6.093702
• 发表时间: 2021-09
• 期刊: Physical Review Fluids
• 影响因子: 2.7
• 作者: Malekanfard, Amirreza;Liu, Zhijian;Zhao, Hui;Song, Yongxin;Xuan, Xiangchun
• 通讯作者: Xuan, Xiangchun