Anions effect on ion transport properties of polyelectrolyte modified single conical nanopores

Highlights: • Single conical nanopores are fabricated in polymer membrane by track-etching technique. • Nanopore surface is modified by electrostatic immobilization of cationic polyelectrolytes. • Transport properties of positively charged conical nanopores are studied. • Concentration-dependent effect of various anions on nanopore transport is investigated. • The anions interaction with the positive charges leads to changes in the nanopore electrical readout. Here we present screening effect of various anions on nanopore fixed surface charges. The anions could not induce significant change in ion transport through negatively charged nanopore. For positively charged nanopore, the order of monovalent anions effect is: H₂PO₄⁻ > HCO₃^– > NO₃^– > BrO₃⁻ ~ Cl⁻. The divalent HPO₄²⁻ exhibits significant changes in the rectified ion flux, while SO₄²⁻ could not induce any noticeable change even at higher concentrations. Our experimental results demonstrated the ability of various anions to interact with fixed surface charges and their effect on nanopore transport characteristics.