Discontinuous Transition in Electrolyte Flow through Charge-Patterned Nanochannels

We investigate the flow of an electrolyte through a rigid nanochannel decorated with a surface charge pattern. Employing lattice Boltzmann and dissipative particle dynamics methods, as well as analytical theory, we show that the electrohydrodynamic coupling leads to two distinct flow regimes. The accompanying discontinuous transition between slow, ionic, and fast, Poiseuille flows is observed at intermediate ion concentrations, channel widths, and electrostatic coupling strengths. These findings indicate routes to design nanochannels containing a typical aqueous electrolyte that exhibit a digital on-off flux response, which could be useful for nanofluidics and ionotronic applications.Received 10 January 2024Accepted 26 June 2024DOI:https://doi.org/10.1103/PhysRevLett.133.078201© 2024 American Physical SocietyPhysics Subject Headings (PhySH)