Emulsions: Principles and preparation - Making emulsions using membranes and microchannels - Membrane emulsification
12 important questions on Emulsions: Principles and preparation - Making emulsions using membranes and microchannels - Membrane emulsification
What mechanism is used for cross-flow membrane emulsification?
What is the drag force?
Which 2 forces interact on a droplet during cross-flow membrane emulsification?
Interfacial tension --> keep the droplet at pore mouth
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Explain what happens to the Laplace pressures with cross-flow emulsification at the SPG membrane
The cross-flow does not have much influence on the process, it is driven by the interfacial tension.
At what kind of flow rate does the spontaneous snap off at cross-flow membrane emulsification take place?
When does spontaneous snap off take place?
What mechanism is used for dead-end (premix) membrane emulsification?
How are the pre-emulsion and the droplet size distribution related?
Every pass, the number of small droplets increases and large droplets decreases, until the emulsion consists only of small droplets.
What are 3 break-up mechanisms of dead-end (premix) membrane emulsification?
- Snap-off due to localised shear
- Break-up due to interfacial tension effects
- Break-up due to steric hindrance
What is the typical droplet size in dead-end (premix) membrane emulsification? And what is it dependent on?
The droplet size is hardly dependent on the flux through the membrane or the volume fraction of the dispersed phase.
However, the flux is dependent on the volume fraction of the dispersed phase.
What is a disadvantage of dead-end (premix) membrane emulsification?
What is the mechanism of phase inversion in premix membrane emulsification?
The same (O/W or W/O) will be obtained when the membrane is wetted with by the continuous phase, like in cross-flow and dead-end membrane emulsification.
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