How fast can fluids squeeze through micro-pores?

TL;DR

This paper models pressure and osmosis-driven flow through molecular-sized channels using a symmetric exclusion model, revealing nonlinear behaviors and maximum flow rates influenced by pore properties and conditions.

Contribution

It introduces an analytic framework for steady-state flow in molecular channels, including effects of internal defects, highlighting complex nonlinear dependencies.

Findings

Flow rates exhibit a maximum depending on pore radius and energetics.

Nonlinear behaviors suggest new diagnostic experiments.

Exact mean-field results for defective pores are provided.

Abstract

We use a one dimensional symmetric exclusion model to study pressure and osmosis driven flows through molecular-sized channels, such as biological membrane channels and zeolite pores. Analytic expressions are found for the steady-state flow which show rich nonlinear behavior. We find a maximum in the flow rates depending upon pore radius, pore energetics, reservoir temperature, and driving force. We also present exact mean-field results of transport through pores with internal defects. The interesting nonlinear dependences suggest numerous diagnostic experiments in biological and zeolitic systems which may reveal the features presented.