Coherent lipid acyl tail correlation dynamics measured using polarized quasi-elastic neutron scattering

Lipid molecules self-assemble in aqueous environment to form bilayers. Although the elastic and viscous properties of the bilayers are controlled by molecular orientations and dynamics, detailed mechanisms of how macroscopic membrane properties relate to the molecular scale structure and dynamics. In a previous study, the acyl tail correlation dynamics represented two characteristic relaxation processes in the fluid phase, where the fast dynamics related to the density fluctuations of acyl tails of a lipid molecule while the slower dynamics was considered to the structural relaxation of lipid molecules. The relaxation times were used to estimate membrane viscosity and the extracted values were close to the average of the reported values in literature. In order to further understanding the microscopic origins of membrane viscosity, more detailed analysis of neutron scattering data were performed. Namely, components of distinct and self-correlations of the acyl tail dynamics are separated by employing polarized quasi-elastic neutron scattering techniques.