FORMATION OF MICELLES WITH COMPLEX COACERVATE CORES

Micelles are commonly regarded as colloidal structures spontaneously f ormed by amphiphilic molecules, that is, molecules consisting of two d istinct parts of which one is soluble and the other is insoluble. This definition is too restrictive: other kinds of molecules can also form micelles. We report on the formation of micelles from a mixture of a (water-soluble) polyanion and a diblock copolymer with two entirely wa ter-soluble blocks: one cationic and one neutral. The cationic block f orms a complex coacervate with poly(acrylic acid); the neutral block s erves as a stablizing block, prohibiting the growth of the complex coa cervate droplets to macroscopic sizes. The formation of these micelles upon mixing is preceded by a macroscopic phase separation. The polyme r-rich phase which initially forms rearranges into a stable micellar s olution.