Let us take a nano-emulsion with water as continuous phase. It contains micelles made of surfactant molecules with oil phase present inside them. Oil/surfactant ratio defines the size of a micelle. When water and surfactant are present without any oil added (oil/surfactant ratio=0.0), there will be empty micelles. The size of a micelle keeps on increasing ( for a given micelle shape) with the addition of oil. In other words, with increase in ratio of oil to surfactant, the micelles swell.

In general, all microemulsions are made of swollen micelles with oil/water inside them.

We use both hydrophilic and Lipophilic emulsifiers in our emulsions, finding harmony between both and the oil phase, in what’s called the HLB (Hydrophilic/Lipophilic balance). Finding this balance, and using the proper emulsifiers, lends strength to the micelle, and limits flocculation, conglomeration and the Ostwalt Ripening making the emulsion more stable.

Its taken years of R&D and development, as well as a healthy dose of trail and error.