Droplet-based microfluidic system for multiple-droplet trapping, storing, and clustering
Droplet-based microfluidics has proven to be a useful tool to investigate heterogeneous reactions that occur between multiple phases due to the reproducible flow patterns and effective mass transport between phases . Nowadays, droplet-based microfluidics is showing its potential for systematic study of the transport across interfaces between different micro reactors since the surfactant layers around micro droplets are in principle permeable to small molecules . In order to study such bio/chemical assays and medium transfer from one droplet to another, droplet paring system in continuous-flow channels  and even static arrays  has been developed and demonstrated. However, a more desirable, but more difficult unit operation for complex assays is to cluster multiple-droplet containing different reagents/samples for various biological and chemical experiments. The objective of this thesis is to study clustering of multiple-droplet in a double-layered microfluidic device integrating multiple functions such as droplet generation, manipulation, trapping, guiding, and storing. The use of guiding tracks and simple forward/backward flows has been incorporated to improve trapping/storing efficiency. The primary goal is to investigate the fluid dynamics and adopt a method to design and simulate the device. The secondary goal is to learn the ability to fabricate the device and demonstrate a large array of different multiple-droplet clustering. Finally, the future goal is to apply the tested device for a wide range of biomedical applications. We expect the proposed strategy will be valuable to study transfer of molecules across the droplets, enzymatic reaction and high throughput bioassay reaction.