An emulsion is a mixture of two or more immiscible liquids – one being oil based and the other water based, or “aqueous.” They are described as “immiscible” liquids because they cannot easily be mixed together without separating.

Simple emulsions are either oil dispersed in an aqueous phase or water dispersed in oil.

To create a stable emulsion and stop your emulsion from separating, you need to add an emulsifier. An emulsifier has a hydrophilic (water liking) end and a lipophilic (oil liking) end. The hydrophilic end is attracted to the aqueous phase and lipophilic end to the oil phase, and this binds them together.

You also need something that can impart a large amount of energy, like a high shear rotor/stator mixer. Unlike a conventional agitator which just moves the two liquid phases around, the high shear mixer sucks the liquids into the workhead and forces them out through the holes in the stator which reduces them to a fine globule size. After a few minutes of intense high-energy mixing the two phases are finely and uniformly dispersed – and a stable emulsion is formed.

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