Development of micro-PIV for electmosmotic flow measurement

用于电渗流量测量的微型 PIV 的开发

基本信息

批准号：
14350089
负责人：
OSHIMA Marie
金额：
$ 9.22万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

A new micro flow diagnostic technique, "micro-PIV", has been developed in order to investigate the electroosmotic flow, which is generated by electrical force in microfluidic devices or systems such as "μTAS". The micro-PIV system consists of a custom-built epifluorescent microscope and several conventional PIV components such as a high-sensitive cooled CCD camera, a high-power pursed laser, synchronizer, PC and so on. Using this optical system and PIV method, any micro flows in the fields of 510 μm x 410 μm can be visualized readily and measured quantitatively with high-spatial resolution. The key features of the present system are reflected-light illumination method with pursed lasers and long working distance, which help to increase the ease of use and expand the application range of the micro-PIV system.The micro-PIV system has been applied to the measurement of various microchannel flows for the purpose of measurement performance evaluation. And then, we measured the electroosmoti … More c flow using the micro-PIV system and evaluated the effects of zeta-potential of both tracer particles and channel surfaces on the flow. The following considerations are derived from the results of PIV and zeta-potential measurements. Firstly, electroosmotic flow in a microchannel shows flat velocity profiles except near the wall. Secondly, electroosmotic flow arises in a PDMS channel even though it assumed to be electrically neutral. Finally, the ion density and the potential (including zeta-potential) in the electrical double layer vary according to additional tracer particles, which leads to changes in electroosmotic velocity profiles. The micro-PIV technique, however, has a disadvantage in obtaining a good quality of particle images. The general micro-PIV system makes use of the epifluorescent microscopy so as to image the tracer particles. Therefore, the micro-PIV images always include projection of whole fluorescent light from not only the focused particles but also the unfocused particles, which decreases the out-of-plane measurement resolution.In order to improve the out-of-plane resolution of micro-PIV, we have developed a new micro-PIV technique, "confocal micro-PIV". Using this confocal micro-PIV system, we can remove the out-of-focus light optically from PIV images and measure velocity distributions within a thin layer of a horizontal cross-sectional plane. As the demonstration of confocal micro-PIV, we have measured the internal flow of the small droplet, and found out three-dimensional flow structure inside the droplet. The confocal micro-PIV technique has proved to be a useful and powerful tool for the experimental study of the electroosmotic flow phenomenon. Less

为了研究电子流，已开发了一种新的微流诊断技术“ Micro-PIV”，该电子流是通过微流体设备或“μTAS”等系统产生的。微型PIV系统由定制的表面显微镜和几种常规的PIV组件，例如高敏感的冷却CCD摄像头，高功率的激光，同步器，PC等。使用这种光学系统和PIV方法，可以轻松地将510μmx410μm场中的任何微滴管可视化，并通过高间隙分辨率进行定量测量。本系统的关键特征是反射光照明方法，具有追踪激光器和较长的工作距离，这有助于提高使用易于使用，并扩展了Micro-PIV系统的应用范围。Micro-PIV系统已应用于测量各种微通道流量以进行测量绩效评估的目的。然后，我们使用Micro-PIV系统测量了ElectronicsMoti…更多的C流，并评估了示踪剂颗粒和通道表面对流动的Zeta势力的影响。以下考虑来自PIV和ZETA电位测量结果。首先，微通道中的电子流量显示出平坦的速度曲线，除了墙壁附近。其次，即使假定具有电中性的电子流动，也会在PDMS通道中产生电子流。最后，电动双层中的离子密度和电势（包括ZETA电位）因其他示踪剂颗粒而变化，这会导致电渗透速度曲线的变化。然而，微PIV技术在获得良好质量的粒子图像方面具有不利地位。一般的微PIV系统利用了落荧光显微镜，以对示踪剂颗粒进行成像。因此，微PIV图像始终包括从聚焦颗粒的整个荧光灯的投影，而且还包括未关注的颗粒，从而降低了平面外测量的分辨率。使用此共聚焦微PIV系统，我们可以从PIV图像中删除异常光，并在水平横截面平面的薄层内测量速度分布。作为共聚焦微型PIV的演示，我们测量了小滴的内部流动，并发现了液滴内部的三维流量结构。共聚焦微型PIV技术已被证明是用于电子流现象的实验研究的有用且功能强大的工具。较少的