Direct X-Ray Study of the Molecular Tilt in Dipalmitoy Lecithin Bilayers
Well-ordered multilayer systems of dipalmitoyl lecithin and water containing enough material for X-ray diffraction were prepared. They consisted of 100 subsystems alternating with mylar films, each film and subsystem being 5 μm thick. The tilt of the hydrocarbon chains away from the layer normal was measured in the water-saturated gel phase (LA) as a function of temperature. The angle varied between 15° and 8° with the maximum at 10°C. The tilt was directed along one of the basic vectors of the quasihexagonal lattice of the hydrocarbon chains.