Direct Observation of Dispersion and Mixing Processes in Microfluidic Systems
Direct Observation of Dispersion and Mixing Processes in Microfluidic Systems
复制标题
直接观察微流体系统中的分散和混合过程
作者：
Y. Takabayashi;T. Fujino;T. Korenaga
在玻璃微通道中，直接观察了样品溶质（碱性蓝3染料和KMnO_4水溶液）在层流中的扩散现象、分散和混合过程。利用彩色样品分散和混合过程的CCD相机图像进行准稳态紫外-可见吸收光谱分析，并基于无量纲参数τ（代表对扩散系数和通道截面进行重整化的流动时间）讨论吸光度变化（ΔAbs）。结果表明，在相同的微通道制备方法下，即使溶液和微通道尺寸在层流中不同，ΔAbs对τ的依赖性也几乎相同。基于这一基本结果，我们计算了2，3-二氨基萘（DAN）和NO_2^-在2 µL min^-1流速下反应所需的微通道总长度，所得值（约100 mm）与我们之前的微芯片研究结果非常吻合。这两个结果对于设计微通道的宽度、深度和长度以控制化学反应时间是有用的。
The diffusion phenomena, dispersion and mixing processes of the sample solute (Basic Blue 3 dye and KMnO_4 aqueous solutions) were directly observed in laminar flow in glass microchannels. Quasi steady-state UV-visible absorption spectrometry was carried out using CCD camera images of the colored sample dispersion and mixing processes, and the absorbance change (ΔAbs) was discussed based on the dimensionless parameter, τ which represents the flow time renormalized to the diffusion coefficient and the channel cross section. It was found that ΔAbs showed almost the same τ dependence, even though the solutions and the microchannel sizes differed in laminar flow, if the microchannel fabrication method was the same. On the basis of this fundamental result, the total microchannel length required for the reaction of 2,3-diaminonaphthalene (DAN) and NO_2^– at a flow rate of 2 µL min^–1 was calculated, and the obtained value (∼100 mm) showed very good agreement with our previous microchip research. It was concluded that both results were useful for designing the microchannel width, depth and length to control the chemical reaction time in recent microfluidic systems.