一种液滴生成后端耦合微腔阵列的液滴捕获行为

In the droplet microfluidic technology, the microchambers array device is often used to locate and separate granular substances including droplets. However, under the condition of passive microfluidic, there is a coordination challenge between the high dynamic nature of the droplet generation process and the relative staticness required for the droplet location and separation, which brings some difficulties to the efforts to integrate the devices into the integration process. In this paper, a droplet microfluidic device coupled with a microchambers array at the back end of droplet generation is reported, and the droplet capture behavior in this droplet microfluidic device is discussed. The front-end of the coupled droplet microfluidic device is a flow-focusing droplet generator, with 1wt % Span80 soybean oil as the continuous phase and 1wt % sodium alginate as the dispersed phase. Under the two-phase ( continuous phase and discrete phase ) flow ratio Qc / Qd = ( 2 ~ 10 ), the droplet flow in the droplet mode can be generated from 163.2 ± 5.9μm to 364.4 ± 8.2μm ( CV < 4 % ). After the generated droplets flow through the serpentine channel, they are pushed into the back-end microchambers array device.The entrance of the microchambers array device is the continuation of the serpentine channel, but the parallel serpentine channels are communicated by a series of branch channels. In particular, the microchambers array is configured on each branch channel. Furthermore, we investigate the effects of two kinds of microchambers array arrangement ( 1 × 15 and 6 × 10 ) and two kinds of microchambers inlet channel structure ( straight and flow-enhancing guide grooves ) on droplet positioning and trapping efficiency.The results show that the capture efficiency of 1 × 15microchambers array decreases with the increase of two-phase flow ratio when the microcavity inlet is straight channel structure. When Qd = 0.3μl / min and Qc / Qd = 2, the capture efficiency of droplet ( diameter ~ 360μm ) can reach 66.7 %. When the inlet of the microchambers branch channel is a flow-enhancing guide grooves, the maximum capture efficiency is improved to 86.7 % under the same flow conditions. When the 1 × 15 microchambers array with a flow-enhancing guide groovesis increased to 6 × 10 microchambers array, the maximum capture efficiency can still reach 71.7 % under the same flow rate above. These preliminary results suggest that the droplet flow distribution of each microchambers inlet channel structure has an important influence on the droplet capture efficiency in microchambers array.