The unbinding transition of mixed fluid membranes

TL;DR

This paper presents a phenomenological model for the unbinding transition of multi-component fluid membranes, linking phase separation and membrane-substrate distance, and predicts a first-order transition below a critical temperature.

Contribution

It introduces a novel theory analogous to Flory-Huggins for polymers to explain membrane unbinding and phase coexistence in multi-component membranes.

Findings

Unbinding transition can be first-order below a critical temperature.

Phase coexistence between two unbound phases observed.

Coupling between phase separation and membrane distance explains experimental results.

Abstract

A phenomenological model for the unbinding transition of multi-component fluid membranes is proposed, where the unbinding transition is described using a theory analogous to Flory-Huggins theory for polymers. The coupling between the lateral phase separation of inclusion molecules and the membrane-substrate distance explains the phase coexistence between two unbound phases as observed in recent experiments by Marx et al. [Phys. Rev. Lett. 88, 138102 (2002)]. Bellow a critical end-point temperature, we find that the unbinding transition becomes first-order for multi-component membranes.