Membrane emulsification (ME) is a relatively novel technique for producing all types of single and multiple

emulsion An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Altho ...

s for DDS (

drug delivery systems A route of administration in pharmacology and toxicology is the way by which a medication, drug, fluid, poison, or other substance is taken into the body. Routes of administration are generally classified by the location at which the substance i ...

), solid micro carriers for encapsulation of drug or nutrient,

solder Solder (; NA: ) is a fusible metal alloy used to create a permanent bond between metal workpieces. Solder is melted in order to wet the parts of the joint, where it adheres to and connects the pieces after cooling. Metals or alloys suitable ...

particles for surface-mount technology, mono dispersed polymer microspheres (for analytical column packing, enzyme carriers, liquid crystal display spacers, toner core particles). Membrane emulsification was introduced by Nakashima and Shimizu in the late 1980s in Japan.

Description

In this process, the dispersed phase is forced through the pores of a microporous

membrane A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. ...

directly into the continuous phase. Emulsified droplets are formed and detached at the end of the pores with a drop-by-drop mechanism. The advantages of membrane emulsification over conventional emulsification processes are that it enables one to obtain very fine emulsions of controlled droplet sizes and narrow droplet size distributions. Successful emulsification can be carried out with much less consumption of emulsifier and energy, and because of the lowered

shear stress Shear stress, often denoted by (Greek: tau), is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. ''Normal stress'', on the ...

effect, membrane emulsification allows the use of shear-sensitive ingredients, such as starch and proteins. The membrane emulsification process is generally carried out in

cross-flow Crossflow may refer to: * Ford Crossflow, the 1967 version of the Ford Kent engine * Crossflow cylinder head * Cross-flow fan, a type of mechanical fan * Cross-flow filtration In chemical engineering, biochemical engineering and protein purificat ...

(continuous or batch) mode or in a stirred cell (batch). A major limiting factor of ME was the low dispersed phase flux. In order to expand the industrial applications, the productivity of this method had to be increased. Some research has been aimed at solving this problem and others, such as membrane fouling. High dispersed phase flux has now been shown to be possible using single-pass annular gap crossflow membranes.

References

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External links

Membrane Emulsification: Process Principles by Anneke Gijsbertsen-Abrahamse

CFD Analysis of generation of Oil-in-water Emulsion using Rectangular Straight-through Microchannel by Kobayashi et. al.

Membrane Emulsification video by Richard G. Holdich

ITM-CNR, Calabria, Italy

Micropre Technologies, UK

SPG Technology Co, Japan
Physical chemistry Membrane technology