The poor control and regulation of droplets limit the applications of negative-pressure-driven-droplet-generator (NPDDG). Here, we present a simple method to control droplet size in NPDDG via varying the oil viscosity. Depending on the infinite inter-solubility of high viscous mineral oil and low viscous hexadecane, we obtain a series of oils with kinematic viscosities linearly varied from 4.2 mm2/s to 194.6 mm2/s. By using these oils as continuous phases, mono-disperse droplets are fabricated with controllable size in NPDDG. This viscosity based droplet regulation method is effective, reliable, and compatible with scale-up processes. Compared with droplet generator driven by positive pressure, the presented method can fabricate hydrogel particles massively, without complicated multi-layer chip structure and complex fluid controlling, which may extend the potential of NPDDG in droplets based high throughput assay or large-scale materials synthesis.
Hanlin li, Yijun Xue, Meng Xu, Wenfeng Zhao, Chenghua Zong, Xiaojun Liu, Qingquan Zhang
Accepted manuscript online: 22 April 2017Full publication history