Abstract
Droplet-based microfluidics has been extensively developed for the highly diverse applications from diagnostics to microreactors. Since interfacial phenomena become dominant with the decreased length scale of system, this study exploits an interfacial flow controlled by a patterned optical heating for the microfluidic droplet manipulation. We developed a reducing exposure optical system which enabled arbitrary shaped light irradiation characterized by a photomask in the microchannel to control droplets. In this study, control performance for droplets with the volumes from 5 to 65 pL by patterned heating was investigated. Inclined bar, focusing and V-shaped pattern heating provides remote control of droplets as lateral transportation, alignment and trapping, respectively. We have also examined the dependence of parameters, i.e., laser power, flow rate and droplet size. According to the experimental results, it is clarified that the larger droplet can be manipulated easily and that stronger light induced stronger driving force on droplet.
