The irreversible thermodynamics of curved lipid membranes II: Permeability and osmosis

TL;DR

This paper develops a thermodynamic framework for curved lipid membranes, linking mechanics and permeability, and introduces a new driving force for permeability based on entropy production analysis.

Contribution

It combines irreversible thermodynamics with integral theorems to model deforming membranes and identifies deviatoric stress as a novel permeability driver.

Findings

Derived an equation for internal entropy production at membranes.

Identified deviatoric stress as a new thermodynamic force for permeability.

Provided comprehensive equations of motion and boundary conditions.

Abstract

We present a theory that combines the framework of irreversible thermodynamics with modified integral theorems to model arbitrarily curved and deforming membranes immersed in bulk fluid solutions. We study the coupling between the mechanics and permeability of a viscous and elastically-bendable membrane, and a multi-component bulk fluid solution. An equation for the internal entropy production for irreversibilities at the membrane is derived, determining the generalized thermodynamic forces and fluxes, from which we identify the deviatoric stress as a novel driving force for permeability. A complete set of equations of motion, constitutive laws, and boundary conditions to model the lipid membrane and bulk fluid system are provided.