Steric Interactions in a Model Multimembrane System: A Synchrotron X-Ray Study

Abstract

We report a high-resolution x-ray study of a model multilayer fluid membrane system in the lyotropic ${L}_{\ensuremath{\alpha}}$ phase of a quaternary microemulsion system. The structure factor exhibits power-law behavior characteristic of a Landau-Peierls system. As a function of intermembrane distance $3.8 \mathrm{nm}\ensuremath{\le}d\ensuremath{\le}16.3 \mathrm{nm}$, the exponent $\ensuremath{\eta}(d)$ which describes the algebraic decay of layer correlations is predicted by the model of Helfrich where entropic steric repulsions dominate intermembrane interactions.