Leaky Membrane Dynamics

TL;DR

This paper explores how particle size and pore geometry cause complex, kinetically driven flow behaviors in membranes, leading to metastable states that influence diffusion without relying on traditional potential-based forces.

Contribution

It introduces a heuristic model and analyzes geometries that demonstrate kinetically induced metastable states in membrane diffusion.

Findings

Certain geometries promote metastable blocking states.

Diffusion behavior is purely kinetic, independent of potential or dissipation.

The heuristic model captures key qualitative features of the system.

Abstract

A concentration difference of particles across a membrane perforated by pores will induce a diffusive flux. If the diffusing objects are of the same length scale as the the pores, diffusion may not be simple, objects can move into the pore in a configuration that requires them to back up in order to continue forward. A configuration that blocks flow through the pore may be statistically preferred, an attracting metastable state of the system. This effect is purely kinetic, and not dependent on potentials, friction or dissipation. We discuss several geometries which generate this effect, and introduce a heuristic model which captures the qualitative features.