Lee Yonghun, Seder Islam, Kim Sung-Jin
Department of Mechanical Engineering, Konkuk University Seoul 05029 Republic of Korea
RSC Adv. 2019 Apr 2;9(18):10345-10351. doi: 10.1039/c8ra09756a. eCollection 2019 Mar 28.
Surface tension-driven flow is widely used, owing to its spontaneous motion, in microfluidic devices with single channel structures. However, when multiple channels are used, unwanted backflow often occurs. This prevents precise and sophisticated solution flow, but has been rarely characterized. We hypothesize that, with an analytical model, the parameters that influence backflow can be systematically characterized to minimize the backflow. In a microfluidic network, inlet menisci and channels are modeled as variable pressure sources and fluidic conductors, respectively. Through the model and experiment, the influence of each network element on the backflow strength is studied. Backflow strength is affected by the interplay of multiple inlet-channel elements. With the decrease (increase) of the fluidic channel conductance (inlet size), the backflow pressure of the corresponding inlet decreases. On the other hand, backflow volume reaches its peak value during the radius change of the corresponding inlet. In networks consisting of five inlet-channel elements, backflow pressure decreases with increasing step number. Our results provide the foundations for microfluidic networks driven by the Laplace pressure of inlet menisci.
由于表面张力驱动的流动具有自发运动的特性，它在具有单通道结构的微流控装置中得到了广泛应用。然而，当使用多个通道时，常常会出现不需要的回流现象。这阻碍了精确而复杂的溶液流动，但其特征却鲜有描述。我们推测，通过一个分析模型，可以系统地表征影响回流的参数，从而将回流降至最低。在微流控网络中，入口弯月面和通道分别被建模为可变压力源和流体导体。通过该模型和实验，研究了每个网络元件对回流强度的影响。回流强度受多个入口 - 通道元件相互作用的影响。随着流体通道电导（入口尺寸）的减小（增大），相应入口的回流压力降低。另一方面，在相应入口半径变化期间，回流量达到峰值。在由五个入口 - 通道元件组成的网络中，回流压力随着步数的增加而降低。我们的结果为基于入口弯月面拉普拉斯压力驱动的微流控网络奠定了基础。
