title: Relaxation dynamics of two-component fluid bilayer membranes.
abstract: We theoretically investigate the relaxation dynamics of a nearly flat binary lipid bilayer membrane by taking into account the membrane tension, hydrodynamics of the surrounding fluid, inter-monolayer friction and mutual diffusion. Mutual diffusion is the collective irreversible process that leads to homogenization of the density difference between the two lipid species. We find that two relaxation modes associated with the mutual diffusion appear in addition to the three previously discussed relaxation modes reflecting the bending and compression of the membrane. Because of the symmetry, only one of the two diffusive modes is coupled to the bending mode. The two diffusive modes are much slower than the bending and compression modes in the entire realistic wave number range. This means that the long time relaxation behavior is dominated by the mutual diffusion in binary membranes. The two diffusive modes become even slower in the vicinity of the unstable region towards phase separation, while the other modes are almost unchanged. In short time scales, on the other hand, the lipid composition heterogeneity induces in-plane compression and bending of the bilayer.
authors.affiliation: Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 192-0397, Tokyo, Japan. okamotor@tmu.ac.jp.|Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS, F-75205, Paris, France. okamotor@tmu.ac.jp.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Okamoto
authors.affiliation: Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 192-0397, Tokyo, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kanemori
authors.affiliation: Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University, 192-0397, Tokyo, Japan.|Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS, F-75205, Paris, France.
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Komura
authors.affiliation: Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Matière et Systèmes Complexes (MSC), UMR 7057 CNRS, F-75205, Paris, France.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Fournier
mesh_terms: D004058:Diffusion; D017276:Friction; D057446:Hydrodynamics; D008051:Lipid Bilayers / Q000737:chemistry*; D011312:Pressure
chemical_list: D008051:Lipid Bilayers
keywords: Soft Matter: Interfacial Phenomena and Nanostructured Surfaces