  By evaporating a drop of lipid dispersion we generate the myelin morphology
often seen in dissolving surfactant powders. We explain these puzzling
nonequilibrium structures using a geometric argument: The bilayer repeat
spacing increases and thus the repulsion between bilayers decreases when a
multilamellar disk is converted into a myelin without gain or loss of material
and with number of bilayers unchanged. Sufficient reduction in bilayer
repulsion can compensate for the cost in curvature energy, leading to a net
stability of the myelin structure. A numerical estimate predicts the degree of
dehydration required to favor myelin structures over flat lamellae.
