A Microfluidic Platform for Parallel Synchronization of Multiple Droplets by Ladder-Like Fluidic Network

H. Lee, L. Xu, K.W. Oh
SUNY at Buffalo, US

Keywords: droplet, synchronization, dilution


We present a method for a parallel synchronization of multiple droplets with different concentrations in a continuous flow manner. Our previous device was modified (e.g., a synchronized droplet pairing (n=2) using a ladder-like fluidic network) for a synchronization of three droplets (n=3) with different concentrations where dilution module is integrated. Our device was tested by varying the flow rates of oil and water. It is critical to control the size of droplets in this device. The size of the generated droplets must be larger than that of the main flow channel to allow strong cross-interaction between the channels. If the droplet size is smaller than that of the channel, the carrier oil can flow across the small droplets, causing weak cross-interaction. For this reason, we investigated the size of droplets as a function of flow rate ratio. The droplet generation frequency difference is also important parameter for the synchronization because excess droplets make it difficult to be a stable synchronization process. At the given condition, the maximum synchronization efficiency was 92.1%. We expect that, in principle, more than three droplets (n=3) with different concentrations would be synchronized using the proposed method.