Anomalous phase sequences in lyotropic liquid crystals

Lee, Won Bo; Mezzenga, Raffaele; Fredrickson, Glenn H.

doi:10.1103/PhysRevLett.99.187801

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Journal article

Anomalous phase sequences in lyotropic liquid crystals

Lee, Won Bo Department of Chemical Engineering, University of California, Santa Barbara, USA
Mezzenga, Raffaele Department of Physics, University of Fribourg, Switzerland - Nestlé Research Center, Vers-Chez-Les-Blanc, Lausanne, Switzerland
Fredrickson, Glenn H. Department of Chemical Engineering, University of California, Santa Barbara, USA - Materials Research Laboratory, University of California, Santa Barbara, USA - Department of Materials, University of California, Santa Barbara, USA

31.10.2007

Published in:

Physical Review Letters. - 2007, vol. 77, p. 187801

English We present a coarse-grained model in order to describe the unusual sequence of mesophases observed in aqueous solutions of nonionic lipids, such as monoolein. The lipid molecules are modeled as a rigid head and a flexible Gaussian tail, and water is treated explicitly. A key component of the model is thermally reversible hydrogen bonding between the lipid head and water resulting in changes in both head volume and the interactions of the hydrated head with its surroundings. Phase diagrams obtained from unit-cell self-consistent field simulations capture the qualitative thermotropic and lyotropic phase behavior of the monoolein-water system. The unusual phase sequences result from a competition between hydrogen bond formation, changes in head volume and interactions, lipid tail entropy, and the hydrophobic effect.

Faculty

Faculté des sciences et de médecine

Department

Département de Physique

Language