Mechanical Engineering Department, University of Washington, Seattle, Washington 98195, USA.
Biomicrofluidics. 2012 Jun;6(2):26501-2650112. doi: 10.1063/1.4720394. Epub 2012 May 18.
In this paper, we present a simple procedure to incorporate commercially available external pressure transducers into existing microfluidic devices, to monitor pressure-drop in real-time, with minimal design modifications to pre-existing channel designs. We focus on the detailed fabrication steps and assembly to make the process straightforward and robust. The work presented here will benefit those interested in adding pressure drop measurements in polydimethylsiloxane (PDMS) based microchannels without having to modify existing channel designs or requiring additional fabrication steps. By using three different devices with varying aspect ratio channels ([Formula: see text], width/depth), we demonstrate that our approach can easily be adapted into existing channel designs inexpensively. Furthermore, our approach can achieve steady state measurements within a matter of minutes (depending on the fluid) and can easily be used to investigate dynamic pressure drops. In order to validate the accuracy of the measured pressure drops within the three different aspect ratio devices, we compared measured pressure drops of de-ionized water and a 50 wt. % glycerol aqueous solution to four different theoretical expressions. Due to the deformability of PDMS, measured pressure drops were smaller than those predicted by the rigid channel theories (plate and rectangular). Modification of the rigid channel theories with a deformability parameter α provided better fits to the measured data. The elastic rectangular expression developed in this paper does not have a geometric restriction and is better suited for microchannels with a wider range of aspect ratios.
在本文中，我们提出了一种简单的方法，将市售的外部压力传感器集成到现有的微流控设备中，以实时监测压降，对现有通道设计的修改最小。我们专注于详细的制造步骤和组装，以使该过程简单而稳健。这里介绍的工作将使那些有兴趣在基于聚二甲基硅氧烷（PDMS）的微通道中添加压降测量的人受益，而无需修改现有通道设计或需要额外的制造步骤。通过使用具有不同纵横比通道的三个不同设备（[公式：见文本]，宽度/深度），我们证明我们的方法可以轻松地廉价地应用于现有通道设计。此外，我们的方法可以在几分钟内（取决于流体）实现稳定状态测量，并且可以轻松用于研究动态压降。为了验证在三个不同纵横比设备中测量的压降的准确性，我们将去离子水和 50wt.%甘油水溶液的测量压降与四个不同的理论表达式进行了比较。由于 PDMS 的可变形性，测量的压降小于刚性通道理论（板和矩形）预测的压降。用可变形参数α修改刚性通道理论可以更好地拟合测量数据。本文中开发的弹性矩形表达式没有几何限制，更适合具有更宽纵横比范围的微通道。
