Abstract
Step emulsification is one of the widely used microfluidic methods for droplet generation. However, as is the case with the shear-induced droplet generation method, this method faces the challenge of the low monodispersity caused by the satellite droplets. Meanwhile, deterministic lateral displacement (DLD), a passive microfluidic separation method, has been attracting a considerable attension recently, because it can separate particles based on their sizes easily. In this study, we have demonstrated generation and separation of 1,6-hexanediol diacrylate (HDDA) droplets using a microfluidic device comprised of arrayed micronozzles for step emulsification and micropillar arrays for DLD separation on a chip. The HDDA containning 1% photo initiator (DAROCUR 1173) and 2 wt% aqueous polyvinyl alcohol (PVA) solution were used as the disperse phase and the continuous phase, respectively. The Dc of the device, which is the separation boundary, was set at 27.8 um.The main and satellite HDDA droplets were generated at the edge near the micronozzles. Then, after flowing into the DLD micropillar array, the main droplets (diameter, 47 um) flowed at a small angle towards the sidewall (displacement mode), while the satellite droplets (diameter, < 5 um) migrated along the flow direction (zigzag mode).
