Surface tension in bilayer membranes with fixed projected area

TL;DR

This paper investigates the elastic response of bilayer membranes with fixed projected area, measuring two distinct surface tensions related to stretching and shape deformations through simulations and a simple theoretical model.

Contribution

It introduces a model that relates two different surface tensions in bilayer membranes and validates it with computer simulation data.

Findings

Surface tensions differ for stretching and shape deformations.

Surface tensions vanish at different projected areas.

The simple theory successfully explains the simulation results.

Abstract

We study the elastic response of bilayer membranes with fixed projected area to both stretching and shape deformations. A surface tension is associated to each of these deformations. By using model amphiphilic membranes and computer simulations, we are able to observe both the types of deformation, and thus, both the surface tensions, related to each type of deformation, are measured for the same system. These surface tensions are found to assume different values in the same bilayer membrane: in particular they vanish for different values of the projected area. We introduce a simple theory which relates the two quantities and successfully apply it to the data obtained with computer simulations.