Coexisting lamellar phases in water-oil-surfactant systems induced by the addition of an amphiphilic block copolymer.
We report here a pioneering study using quadrupolar splitting NMR to detect new phases and phase compositions in the quasi-ternary microemulsion system water-decane-C(10)E(4)/PEP5-PEO5. The striking observation is that at certain compositions the polymer is apparently no longer incorporated into the membranes of the lamellar phase due to space restrictions. The polymer therefore induces a phase separation into two different lamellar phases L(alpha)(1) and L(alpha)(2) such that it fits into L(alpha)(1) while the excess surfactant forms a polymer-free L(alpha)(2) phase.
Frank
Christian
C
Institut für Physikalische Chemie, Universität zu Köln, Luxemburger Str. 116, D-50939 Köln, Germany.
Strey
Reinhard
R
Schmidt
Claudia
C
Stubenrauch
Cosima
C