Pulido de Torres C., Amici E., Gallarino A., Da Silva M., Jousse F.
Unilever, UK
Keywords: complex structures, droplets, emulsion
We present Microfluidic technology applied to the production of monodisperse emulsion in a food context. We investigate the effect of surfactants and microdevice geometry on drop size and robust production regimes.
Minimum drop size achievable in a microdevice is influenced by microdevice geometry. An asymptotic minimum size is observed and found to be half of width of the channel, for in-channel break geometries like T junctions, and 80% of the aperture for flow focusing geometries.
Drop sizes decrease continuously with increasing concentration of surfactant although for high concentrations the monodispersity is lost.
A microfluidic device can produce monodisperse, polydisperse emulsion or jet (parallel flow of fluids). Surfactant addition modifies the boundaries of the different production regions. For a surfactant free system the monodisperse production region is considerably smaller, almost half, than when the surfactant is added.
The boundary between jetting and drop production regimes also changes, for each geometry, being noteworthy the increase of drop production region for a Pi junction with respect a flow focusing geometry.
Finally is was found that there seem to be a relationship between drop size and a magnitude related with the capillary number, defined by Q/s (Q, continuous phase flow rate, s interfacial tension).
Journal: TechConnect Briefs
Volume: 2, Technical Proceedings of the 2006 NSTI Nanotechnology Conference and Trade Show, Volume 2
Published: May 7, 2006
Pages: 686 - 689
Industry sectors: Advanced Materials & Manufacturing | Personal & Home Care, Food & Agriculture
Topic: Personal & Home Care, Food & Agriculture
ISBN: 0-9767985-7-3