Collaborative Research: Electrokinetic Transport and Separation in MEMS-fabricated Nanofluidic Channels

1402736 Pennathur/GillespepeUCSB/Rush Pres St Luke Med Ctr这个项目旨在研究纳米流体设备中存在的新分离机制。在这样的纳米通道中，溶液样本沿着两面相距10到100纳米的狭缝移动。在纳米尺度的电动通道中，分子不仅相互作用，而且还与设备的带电墙壁相互作用，以至于这些固/液界面相互作用主导着设备的性能。该项目测试了特殊制造的纳米通道和新型缓冲电解质溶液是否可以大大提高两个类似分析离子的分离能力。具体地说，该项目的目标是在墙壁中嵌入电极，以直接操纵墙壁电荷，从而控制分析物的相对速度。这种制作技术将电极嵌入到墙壁中，可以产生10纳米的狭缝高度。新型缓冲离子的大小从小到大，电荷从1到3不等。本项目旨在通过理论和实验的协同合作，研究基于高表面电荷、高离子价态和限制通道的纳米流控离子传输的新分离技术。具体来说，实验将被用来验证一个基于经典(而不是量子)流体密度泛函理论的模型。然后，该模型将用于预测新的分离机制，因为通过数值建模探索大参数集比使用实验室中的硬件快几个数量级。已发现的潜在机制将在实验室中得到验证，该理论将用于理解分离的物理学。该项目有可能全面展示基于纳米通道的分离的可能性。具体地说，将探索纳米流体通道的基本性质，以确定如何利用双电层进行离子传输和分析物分离。如果成功，该项目将首次系统地测量变化的表面电荷和离子属性(如大小和价态)如何定义双层和传输/分离属性。这一新的基础知识不仅适用于分离科学和工程，而且适用于任何具有双电层作用的物理、化学和生物领域。例如，新的物理见解可以应用于重金属处理、环境监测、能源转换、海水淡化、电池和电化学超级电容器，以提高它们的效率，并可能导致新的设计。拟议的外展活动包括编写课程材料、国际活动和高中生外展。所有这些都描述得很好，似乎都是可以实现的。

1402736Pennathur/GillespieUCSB/Rush Pres St Luke Med CtrThis project aims to investigate novel separation mechanisms that exist in nanofluidic devices. In such nanochannels, a sample of solution is moved down a slit with two walls that are 10 to 100 nanometers apart. In nanoscale electrokinetic channels, molecules not only interact with each other, but also with the charged walls of the device, to the point that these solid/liquid interface interactions dominate the performance of the device. This project tests whether specially-fabricated nanochannels and novel buffer electrolyte solutions can greatly enhance separation of two similar analyte ions. Specifically, this project aims to embed electrodes in the walls to directly manipulate the wall charge and therefore the relative speed of the analytes. The fabrication technique embeds electrodes into the walls and can produce slit heights of 10 nm. The novel buffer ions will vary in size from small to large and charge from +1 to +3. This project aims to investigate new separation techniques based on nanofluidic ion transport at high surface charge, high ion valence, and confining channels using a synergistic collaboration between theory and experiment. Specifically, experiments will be used to validate a model based on classical (not quantum) density functional theory of fluids. Then, the model will be used to predict new separation mechanisms because exploring the large parameter set by numerical modeling is orders of magnitude faster than using hardware in the lab. Potential mechanisms discovered will be then be validated in the lab and the theory used to understand the physics of separation. This project has the potential to show the full range of what is possible for nanochannel-based separations. Specifically, the fundamental properties of the nanofluidic channels will be explored to define how the electrical double layer can be harnessed for ion transport and analyte separation. If successful, this project will, for the first time, systematically measure how changing surface charge and ion properties like size and valence define the double layer and transport/separation properties. This new basic knowledge will not only be applicable to separation science and engineering, but to any area of physics, chemistry, and biology where electrical double layers play a role. For example, the new physical insights can be applied to heavy metal processing, environmental monitoring, energy conversion, desalination, batteries, and electrochemical supercapacitors to increase their efficiency and possibly lead to new designs. Proposed outreach activities include development of course materials, international activities and high school student outreach. All are well described and appear achievable.