Berlin 2001 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 7: Dynamics of Molecular Systems
CPP 7.1: Talk
Tuesday, April 3, 2001, 16:45–17:05, 112
Topological control of reactivity in biomembranes by nanostructured lipid phases — •thomas fischer1, ziad khattari1, peter heinig1, and mathias Lösche2 — 1MPI Kolloid und Grenzflächen, Am Mühlenberg1, 14476 Golm — 2Universität Leipzig, Fakultät für Physik, Linnestr. 5, 04103 Leipzig
Lubrication is a phenomenon of enormous technical relevance. The wetting pro-perties of a lubricant are characterized by the contact angle a, a materials param-eter in three-dimensional (3D) systems. The Physics of wetting within systems of lower dimensionality, such as molecularly thin dipolar interface films, is funda-mentally distinct: Long-range correlations between collinearly oriented dipole moments exist not only in solid phases, as in ferroelectrics in 3D, but also in laterally disordered - fluid or even gaseous - phases due to the symmetry break inferred by the interface. Here we show theoretically and demonstrate experimentally using a Langmuir monolayer that a is not a materials parameter in asymmetric quasi-2D systems but depends on the film structure far away from the three-phase contact point. We find meta-stable a values associated with transitions from complete wetting to partial dewetting, triggered by minute changes of the film area, the surface potential of the coexisting phases, or their mutual line tensions. These findings bear implications for the regulation of biomembrane functions since the phenomenon may influence intramembrane biochemical reactions between protein species dissolved in coexisting phases.