Highly aligned lamellar lipid domains induced by macroscopic confinement

Abstract

We have carried out neutron diffraction experiments on a lipid mixture in a macroscopically confined sample geometry (1 mm gap) and have observed the transformation of bilayered micelles into two distinct orientationally aligned domains of perforated lamellae seemingly littered with defects. Depending on the separation of the confining surfaces, the defects can lie on a two-dimensional centered rectangular lattice where the angle, , between lamellar domains can vary. The particular lamellar phase is shown to be metastable and eventually relaxes, either in time or by perturbation of the sample by centrifugation, into aligned multibilayer stacks of single orientation.