Europhys. Lett, 47 (3), pp. 391-397 (1999)
Micellar morphologies of charged diblock-copolymers
R. R. Netz
Max-Planck-Institut für Kolloid-und Grenzflächenforschung
Kantstr. 55, 14513 Teltow, Germany
MPI of Colloids and Interfaces - Am Mühlenberg, 14424 Potsdam, Germany
(received 16 April 1999; accepted 28 May 1999)
PACS. 82.70 - Disperse systems.
PACS. 61.25Hq - Macromolecular and polymer solutions; polymer melts; swelling.
PACS. 64.70 - Specific phase transitions.
Using scaling arguments, we consider dilute solutions of diblock-copolymers consisting of a strongly hydrophobic block and a charged block in an aqueous salt solution. At low salt, the electrostatic repulsion of the charged block dominates and we find a transition from spherical to cylindrical micelles as the salt concentration increases. At high salt, the elastic energy of the hydrophobic core dominates and bilayers are favored. At intermediate salt concentrations cylindrical, spherical, and bilayer morphologies coexist, suggesting the formation of degenerate, multiply connected structures. The endcap energy of cylindrical micelles is high, suggesting the formation of long or toroidal cylindrical micelles.
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