Nanopore conductance controlled by pH: A Poisson–Nernst–Planck–Navier–Stokes model with polymer brushes

Abstract

This theoretical study models pH-dependent ionic transport in nanopores modified with poly(4-vinylpyridine) (P4VP) brushes using the Poisson–Nernst–Planck–Navier–Stokes equations. We demonstrate how protonation of polymer segments influences nanopore conductance under varying pH conditions. The model accurately predicts ionic conductance as a function of pH, showing excellent agreement with experimental data. A direct relationship is established between the degree of polymer dissociation and conductance, revealing how physicochemical interactions affect ionic distribution and local pH within the nanopore. These insights provide a solid theoretical basis for designing pH-sensitive nanofluidic devices.