Department of Chemical Engineering, National Tsing-Hua University , Hsinchu 30013, Taiwan.
College of Engineering, Chang Gung University , Taoyuan 33302, Taiwan.
Anal Chem. 2018 Feb 6;90(3):2317-2325. doi: 10.1021/acs.analchem.7b04779. Epub 2018 Jan 16.
This paper reports a microfluidic viscometer with an integrated pressure sensor based on electrofluidic circuits, which are electrical circuits constructed by ionic liquid-filled microfluidic channels. The electrofluidic circuit provides a pressure-sensing scheme with great long-term and thermal stability. The viscosity of the tested fluidic sample is estimated by its flow resistance, which is a function of pressure drop, flow rate, and the geometry of the microfluidic channel. The viscometer can be exploited to measure viscosity of either Newtonian or non-Newtonian power-law fluid under various shear rates (3-500 1/s) and temperatures (4-70 °C) with small sample volume (less than 400 μL). The developed sensor-integrated microfluidic viscometer is made of poly(dimethylsiloxane) (PDMS) with transparent electrofluidic circuit, which makes it feasible to simultaneously image samples under tests. In addition, the entire device is disposable to prevent cross-contamination between samples, which is desired for various chemical and biomedical applications. In the experiments, viscosities of Newtonian fluids, glycerol water solutions with different concentrations and a mixture of pyrogallol and sodium hydroxide (NaOH), and non-Newtonian fluids, xanthan gum solutions and human blood samples, have been characterized. The results demonstrate that the developed microfluidic viscometer provides a convenient and useful platform for practical viscosity characterization of fluidic samples for a wide variety of applications.
本文报道了一种基于电流体电路的集成压力传感器的微流控粘度计，电流体电路由填充有离子液体的微流道构成。电流体电路提供了一种具有优异长期和热稳定性的压力感测方案。通过测试流体样品的流动阻力来估计其粘度，流动阻力是压降、流速和微流道几何形状的函数。该粘度计可用于在各种剪切速率（3-500 1/s）和温度（4-70°C）下测量牛顿流体或幂律非牛顿流体的粘度，样品体积小（小于 400μL）。所开发的传感器集成微流控粘度计由聚二甲基硅氧烷（PDMS）制成，具有透明的电流体电路，这使得在测试下同时对样品进行成像成为可能。此外，整个设备是一次性的，以防止样品之间的交叉污染，这对于各种化学和生物医学应用是期望的。在实验中，已经对牛顿流体、不同浓度的甘油水溶液以及焦儿茶酚和氢氧化钠（NaOH）的混合物以及非牛顿流体、黄原胶溶液和人血样本来进行了粘度测量。结果表明，所开发的微流控粘度计为各种应用的流体样品的实际粘度特性提供了一个方便且有用的平台。
