Summary: EUROPHYSICS LETTERS 15 October 1999
Europhys. Lett., 48 (2), pp. 170-176 (1999)
Onset of self-assembly in polymer-surfactant systems
H. Diamant and D. Andelman
School of Physics and Astronomy
Raymond and Beverly Sackler Faculty of Exact Sciences
Tel Aviv University, 69978 Tel Aviv, Israel
(received 8 March 1999; accepted in final form 23 August 1999)
PACS. 61.25Hq Macromolecular and polymer solutions; polymer melts; swelling.
PACS. 61.41+e Polymers, elastomers, and plastics.
PACS. 82.65Dp Thermodynamics of surfaces and interfaces.
Abstract. The onset of self-assembly in a dilute aqueous solution containing a flexible
polymer and surfactant is theoretically studied. Focusing on the effect of the surfactant on
polymer conformation and using a conjecture of partial collapse of the polymer at the onset of
self-assembly, we obtain results which agree with known experimental observations: i) polymer-
surfactant self-assembly always starts at a lower concentration (cac) than the one required for
surfactant-surfactant self-assembly (cmc); ii) in charged systems the cac increases with salt
concentration and is almost independent of polymer charge; iii) in weakly interacting systems
the cac remains roughly proportional to the cmc over a wide range of cmc values. The special
case of amphiphilic side-chain polymers strongly supports our basic conjecture. A similarity is