Effects of channel sizes on traffic of solid in water in oil compound droplets through a vertical channel

Abstract

The purpose of this article is to investigate the effects of channel sizes on the traffic of S/W compound droplets through a vertical channel. Compared with the horizontal channel, a vertical channel can effectively inhabit the contact of compound droplets with the channel wall, thus improving the survival rate. It is also found that the effects of tube length on droplet traffic are always dependent on the oil phase flow rate. In a short tube (L = 2.0 cm), the survival rate increases as the oil phase flow rate increases. This may be due to significant prevention of coalescence among S/W compound droplets under a high oil phase flow rate. However, in a long tube (L = 7.5 cm), the survival rate decreases with increasing oil phase flow rate, because disturbance of a water droplet can peel off the water phase coated on the surface of the solid particles. During the traffic process, the distance between water droplets and S/W compound droplets decreases linearly with time because of the larger diameter of the compound droplets. These study results can provide a useful guide for the preparation of high-throughput S/W compound droplets in a controllable and reproducible manner.

Graphical Abstract

Keywords:

• Channel sizes; S/W compound droplets; survival rate; traffic; vertical T-junction device

Additional information

Funding

We are gratefully to acknowledge the funding from National Natural Science Foundation of China (U1530260 and U51703212).