Instability of a fluctuating biomimetic membrane driven by an applied uniform DC electric field

TL;DR

This study analyzes how a DC electric field destabilizes a biomimetic membrane through electrokinetic effects, highlighting the role of Debye layer charge redistribution and contrasting with previous dielectric models.

Contribution

It provides a detailed electrokinetic stability analysis of lipid membranes under electric fields, emphasizing the influence of Debye layer dynamics and electrolyte concentration differences.

Findings

Maxwell stress causes membrane destabilization.

Increased electrolyte concentration difference suppresses instability.

Results differ from leaky dielectric model predictions.

Abstract

The linear stability of a lipid membrane under a DC electric field, applied perpendicularly to the interface, is investigated in the electrokinetic framework, taking into account the dynamics of the Debye layers formed near the membrane. The perturbed charge in the Debye layers redistributes and generates destabilizing Maxwell stress on the membrane, which outweighs the stabilizing contribution from the electrical body force, leading to a net destabilizing effect. The instability is suppressed as the difference in the electrolyte concentration of the solutions separated by the membrane increases, due to a weakened base state electric field near the membrane. This result contrasts with the destabilizing effect predicted using the leaky dielectric model in cases of asymmetric conductivity. We attribute this difference to the varying assumptions about the perturbation amplitude relative to the Debye length, which result in different regimes of validity for the linear stability analysis within these two frameworks.