Which of the following conditions is necessary for the formation of micelles?

Depending on the precise conditions and the nature of the lipids, three types of lipid aggregates can form when mixed with water. They are micelles, bilayer and liposome. Micelles are spherical structures that contain anywhere from a few dozen to a few thousand amphipathic molecule. These molecules are arranged with their hydrophobic regions aggregated in the interior where water is excluded and their hydrophilic head groups at the surface, in contact with water.