The stratum corneum (SC), the outermost layer of the mammalian skin, exhibits the main skin barrier. To know the internal structure and hydration behaviour on the molecular level is essential for studying the SC barrier function and for the design of rational drug delivery systems. Ceramides (CERs) as the major constituent of the multilamellar organized SC lipid matrix are of particular interest. In the present thesis, the ω-acylceramides CER[EOS] and CER[EOP] which are regarded to be crucial for skin barrier properties, were firstly characterised concerning their physicochemical behaviour. The main focus was put on the development of multilamellar model membranes, consisting of synthetic, well-defined structured SC lipids, which should be studied by neutron diffraction. By applying that method the sign of the structure factor could be decided by contrast variation and the calculated neutron scattering length density profile ps(x) allows insights into the internal membrane structure. From the ps(x) of defined composed model membranes, the influence of certain lipids, in particular the one of ceramides, on the membrane nanostructure could be determined. The significant different neutron scattering lengths of hydrogen and deuterium allow the identification of specially marked molecular regions in the membrane profile. Therefore, the impact of the neutron scattering length density profile could be enhanced by the employ of relevant deuterium-labelled lipids. Aside from structure-relations, the localisation of certain molecular regions and the calculation of characteristic membrane parameters, the influence of outside parameters as temperature and humidity on the ps(x) could be determined. Finally, structural influences of single lipid components on the membrane assembling process could be derived from the ps(x) and corresponding schematical models about the arrangement of the lipids on a molecular level were developed.