Electrokinetic Phenomena in Microfluidics and Nanofluidics

微流体和纳流体中的动电现象

• 批准号: RGPIN-2021-02411
• 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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=760429
• 关键词: Electrokinetic; Phenomena; Microfluidics; Nanofluidics

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, including: (1) Electroosmotic flow and electrophoresis of water-immiscible ionic liquids (IL). Because of the high viscosity of ILs, it is necessary to transport ionic liquids in microchannels by electrokinetic means, i.e., electroosmotic flow and electrophoresis. However, there are no any reported works in this regard. Therefore, it is necessary to conduct systematic research to understand the electroosmotic flow of ionic liquids and electrophoretic motion of ionic liquid droplets in microchannels. The expected results of the proposed research will provide not only scientific insight but also the valuable experimental data of electroosmotic flow of ionic liquids and electrophoretic motion of ionic liquid droplets, for future development of microfluidic lab-on-chip technology by using ionic liquids. (2) Electrokinetic phenomena of Janus droplets made by immiscible ionic liquids. In this research, we propose to develop a novel category of ionic liquid Janus droplets by using two immiscible ionic liquids in microfluidic chips, and study electrokinetic transport phenomena of ionic liquid Janus droplets in microchannels. We will investigate (A) How to control the size of the Janus droplets and the proportion of the Janus droplet occupied by one of the two ionic liquids. (B) The electrophoretic mobility of ionic liquid droplets. (C) The velocity of the electrokinetic motion of the Janus droplets as a function of the applied electric field and the proportion of the two immiscible ionic liquids. (D) How to separate the Janus droplets by size and by the proportion of the two immiscible ionic liquids in microfluidic chips. (3) EOF of nanochannels modified with charged polyelectrolyte layers. In order to modulate electrokinetic transport of electrolyte solutions in small nanochannels, this research will examine how to control the surface charge of the channel wall and the cross-section size of nanochannels by using layer-by-layer surface coating of Polybrene (PB) and Dextran sulfate (DS). PB has positive surface charge and DS has negative surface charge and they can be coated on the PDMS surface alternatively (i.e., one positively charged PB layer followed by a negatively charged DS layer, and so on). We will investigate the controlling factors of building multiple coated layers and surface charges of the modified nanochannels, and the effects of these factors on the electroosmotic flow in small nanochannels. We will examine (A) the effects of ionic concentration of the electrolyte solution. (B) the effects of ion size of the electrolytes. (C) the electroosmotic flow (EOF) velocity which will be measured in the modified nanochannels with different numbers of the coated layers by using the current-slope method.

拟议的研究计划旨在研究几种新的动电微流体现象，这些现象对于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，包括：（1）与水不混溶的离子液体的电渗流和电泳（伊利诺伊州）。由于离子液体的高粘度，需要通过动电手段（即电渗流和电泳）在微通道中传输离子液体。但目前尚无这方面的工作报道。因此，有必要开展系统研究，了解微通道中离子液体的电渗流动和离子液体液滴的电泳运动。该研究的预期结果不仅将为离子液体的电渗流和离子液体液滴的电泳运动提供科学见解，而且为未来利用离子液体开发微流控芯片实验室技术提供有价值的实验数据。 (2) 不混溶离子液体形成的Janus液滴的动电现象。在本研究中，我们提出通过在微流控芯片中使用两种不混溶的离子液体来开发一类新型离子液体Janus液滴，并研究离子液体Janus液滴在微通道中的动电传输现象。我们将研究（A）如何控制Janus液滴的尺寸以及两种离子液体之一占据Janus液滴的比例。 (B) 离子液体液滴的电泳迁移率。 (C) Janus 液滴的动电运动速度与所施加的电场和两种不混溶离子液体的比例的函数关系。 (D) 如何根据微流控芯片中两种不混溶离子液体的大小和比例来分离 Janus 液滴。 (3)用带电聚电解质层修饰的纳米通道的EOF。为了调节小纳米通道中电解质溶液的动电传输，本研究将研究如何通过使用聚凝胺（PB）和纳米通道的逐层表面涂层来控制通道壁的表面电荷和纳米通道的横截面尺寸。硫酸葡聚糖（DS）。 PB 具有正表面电荷，DS 具有负表面电荷，它们可以交替涂覆在 PDMS 表面上（即一层带正电荷的 PB 层，然后一层带负电荷的 DS 层，依此类推）。我们将研究构建多层涂层和修饰纳米通道表面电荷的控制因素，以及这些因素对小纳米通道中电渗流的影响。我们将检查 (A) 电解质溶液离子浓度的影响。 (B)电解质离子大小的影响。 (C) 电渗流（EOF）速度，将使用电流斜率法在具有不同数量涂层的修饰纳米通道中测量。