Droplet generation

Glass Capillaries

Double emulsion droplets with multiple inner compartments are useful as artificial cell model and controlled drug delivery vehicles.

We can control the number of inner droplets in double emulsions from 1 to 6. We can also predict the number of inner compartments by adjusting the capillary numbers of the inner, middle and outer fluids.

 

References

R. Al Nuumani, G. Bolognesi, G. and G.T. Vladisavljevic, 2018, Langmuir, 34, 11822-1183.

A.S. Nabavi, G.T. Vladisavljević, V. Manović, 2017 Chemical Engineering Journal, 322, 140

Silicon microchips with straight-through microchannels

We use silicon microchips with horizontally or vertically etched microchannel arrays to produce droplets simultaneously from tens of thousands of microchannels at high production rates. The mechanisms of droplet generation in these microfluidic devices is known as the step microfluidic emulsification. The droplet size is independent on fluid flow rates in the dripping regime.

Collaborators: Prof Mitsutoshi Nakajima, Dr Isao Kobayashi, Dr Nauman Khalid

Reference

G.T.Vladisavljević, E.E. Ekanem, Z. Zhang, N. Khalid, I. Kobayashi, M. Nakajima, 2018. Chemical Engineering Journal, 333, 380-391.

SPG Membranes

SPG membranes are porous glass membranes with interconnected and tortuous pores widely used for membrane emulsification. We prepare emulsions with a narrow particle size distribution in the size range from less than 1 micron to more than 100 microns by either injecting a pure dispersed phase liquid through the membrane (filmed) or pushing a coarsely emulsified mixture of the dispersed and continuous phase through the membrane.

Reference

GT. Vladisavljević, I. Kobayashi, M. Nakajima, R.A. Williams, M. Shimizu and T. Nakashima, 2007, Journal of Membrane Science, 302, 243-253.

Particle Generation

Time-lapse video of phase separation within the template droplets leading to the generation of Janus magnetic particles. These monodisperse particles, composed of a porous polystyrene portion and a nonporous poly(vinyl acetate) portion with embedded oleic acid-coated magnetic nanoparticles, were generated using microfluidic emulsification in a glass capillary device followed by two distinct phase separation events triggered by solvent evaporation.

The magnetic Janus particles could be manipulated by using a magnet. The video shows particle clustering in the external magnetic field due to their magnetization and the rotation of particle clusters in a rotating magnetic field whose direction was manually adjusted.

Reference

R. Al Nuumani, S. K. Smoukov, G. Bolognesi, G.T. Vladisavljević, 2020, Langmuir 36, 42, 12702–12711 (Link)