Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695-7910, USA.
Langmuir. 2010 Jun 15;26(12):9233-9. doi: 10.1021/la100029q.
Microfluidic flow-focusing technology is used to investigate the effect on drop formation due to the production of a surfactant via an interfacial chemical reaction. The reactants are an aqueous solution of sodium hydroxide (NaOH) and a mixture of oleic acid (C(17)H(33)-COOH) and mineral oil, for the dispersed and continuous phase fluids, respectively, at concentration < or = 5 mM. In the absence of a chemical reaction, the drop shapes remain constant from just after breakup into droplets down at the flow-focusing nozzle until the drops exit the channel. In the presence of the chemical reaction, there is modification of the shape depending on the concentration of reactants. The drop speeds, O(10) mm/s, lengths, O(1-100) microm, and relative displacements, O(100-1000) microm, are measured for a variety of flow conditions with observable trends that correlate with the reaction rate, which we rationalize by using the Damkohler number to characterize drop production and transport in these types of flows.
微流控流聚焦技术用于研究通过界面化学反应产生表面活性剂对液滴形成的影响。反应物是氢氧化钠（NaOH）水溶液和油酸（C（17）H（33）-COOH）和矿物油的混合物，分别为分散相和连续相流体，浓度<或=5mM。在没有化学反应的情况下，液滴形状从刚刚分裂成液滴到流聚焦喷嘴处保持不变，直到液滴离开通道。在存在化学反应的情况下，根据反应物的浓度，形状会发生变化。我们测量了各种流动条件下的液滴速度（O（10）mm/s）、长度（O（1-100）μm）和相对位移（O（100-1000）μm），并观察到与反应速率相关的可观测趋势，我们通过使用达姆科勒数来解释这些类型的流动中的液滴产生和传输。
