The comparison between vesicles and micelles is important also for clarifying thermodynamic and kinetic aspects of various aggregation states. Whereas micelles are generally regarded to be thermodynamic equilibrium structures, the thermodynamic stability of vesicles still remains widely debated [13]. The formation kinetics of micelles and vesicles from a saturated fatty acid/soap monomer solution was compared by dialyzing the fatty acid/soap monomers through a cellulose acetate membrane [14•]