Manipulating T-junction chip for the generation of uniform O/W and W/O emulsions

Abstract

The purpose of this study is to generate monodisperse oil-in-water (O/W) and water-in-oil (W/O) emulsions using microfluidic T-junction. The materials of poly methyl methacrylate (PMMA) (hydrophobic), polydimethylsiloxane (PDMS) (hydrophobic) and glass (hydrophilic) were employed for microfluidic chip fabrication. Our strategy is based on the shear focus effect and sheath effect (focusing) to form uniform self-assembling sphere structures, the so-called O/W and W/O emulsions, in the T-junction microchannel. Results show that the size from 31 μm to 43 μm in diameter of O/W emulsions was generated by using the glass-based microfluidic chip. In addition, results show that the size from 70 μm to 220 µm of W/O emulsions was available by utilizing the PMMA-based microfluidic chip. These W/O emulsions were further applied to Ca-alginate microparticles (Ca-alg MPs). And the results also show that the size from 410 μm to 700 μm of UV-Photopolymerized microparticles was available by utilizing the PDMS-based microfluidic chip. The proposed microfluidic chips are capable of generating relatively uniform micro-droplets and have the advantages of actively controlling the droplet diameter, and having a simple and low cost process, with a high throughput.