Hydrodynamic liquid crystal models for lipid bilayers

Research output: Contribution to journalResearch articleContributedpeer-review

Abstract

Coarse-grained continuous descriptions for lipid bilayers are typically based on minimising the Helfrich energy. Such models consider the fluid properties of these structures only implicitly and have been shown to nicely reproduce equilibrium properties. Model extensions that also address the dynamics of these structures are surface (Navier–)Stokes–Helfrich models. They explicitly account for membrane viscosity. However, these models also usually treat the lipid bilayer as a homogeneous continuum, neglecting the molecular degrees of freedom of the lipids. Here, we derive refined models that consider in addition a scalar order parameter representing the molecular alignment of the lipids along the surface normal. Starting from hydrodynamic surface liquid crystal models, we obtain a hydrodynamic surface Landau–Helfrich model for asymmetric lipid bilayers and a surface Beris–Edwards model for symmetric lipid bilayers. The fully ordered case for both models leads to the known surface (Navier–)Stokes–Helfrich models. Besides more detailed continuous models for lipid bilayers, we therefore also provide an alternative derivation of surface (Navier–)Stokes–Helfrich models. The impact on the dynamics is demonstrated by numerical simulations.

Details

Original languageEnglish
Article numberA5
JournalJournal of fluid mechanics
Publication statusPublished - 27 Apr 2026
Peer-reviewedYes

Keywords

Keywords

  • liquid crystals, membranes