Dynamical properties of oriented lipid membranes studied by elastic incoherent neutron scattering

We have studied the H-bonded dynamics in highly oriented lamellar DOTAP-DOPC model membranes as a function of the DOPC/(DOPC+DOTAP) ratio f; by elastic incoherent neutron scatteringin the 100 ps time domain on the spectrometer IN13 at ILL. Motions in the in-plane and out-of plane directions have been explored by orientingthe momentum transfer predominantly parallel and normal to the surface of highly oriented multilayers, respectively. Increasingthe neutral lipid (DOPC) concentration from f ¼ 0:520:8 we reveal a reduction of the dynamics alongthe direction normal to the membrane and an unchanged dynamics on the membrane plane.