Surfactants first migrate to and saturate the air-water interface, lowering surface tension as they orient with their hydrophilic heads in the water and hydrophobic tails away from it.

Once the surface is fully occupied, the system reaches the critical micelle concentration (CMC).  At this point, any additional surfactant molecules can no longer fit at the interface and instead self-assemble in the bulk solution to form micelles, with the hydrophobic tails clustered inward and the hydrophilic heads facing the surrounding water.

These micelles play a critical role in stabilizing emulsions and are fundamental to processes such as emulsion polymerization, where they act as loci for polymer particle formation.