Question

how are emulsions formed by micelles?

Answer 1

Emulsion 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.