Ion-Induced Morphological Changes in “Crew-Cut” Aggregates of Amphiphilic Block Copolymers

Science  21 Jun 1996:
Vol. 272, Issue 5269, pp. 1777-1779
DOI: 10.1126/science.272.5269.1777


The addition of ions in micromolar (CaCl2 or HCl) or millimolar (NaCl) concentrations can change the morphology of “crew-cut” aggregates of amphiphilic block copolymers in dilute solutions. In addition to spherical, rodlike, and univesicular or lamellar aggregates, an unusual large compound vesicle morphology can be obtained from a single block copolymer. Some features of the spontaneously formed large compound vesicles may make them especially useful as vehicles for delivering drugs and as models of biological cells. Gelation of a dilute spherical micelle solution can also be induced by ions as the result of the formation of a cross-linked “pearl necklace” morphology.