Nonspecular neutron scattering from highly aligned phospholipid membranes

We report a neutron scattering study of multilamellar membranes supported on solid substrates. In contrast to previous work, the high degree of orientational alignment allows for a clear distinction between specular and nonspecular reflectivity contributions. In particular, we demonstrate that by using the specific advantages of neutron optics the nonspecular scattering can be mapped over a wide range of reciprocal space. Several orders of magnitude in scattering signal and parallel momentum transfer can easily be recorded in multilamellar stacks of lipid membranes. This opens up the possibility to study fluctuations, and more generally lateral structure parameters of membrane on length scales between a few Angstrom, up to several mu m. The first results obtained for a system of partially hydrated 1,2-dimyristayl-snglycero-3-phosphatidylcholine (DMPC) indicate strong deviations from the predictions of the standard Caille model.