Surface charge regulation of functionalized conical nanopore conductance by divalent cations and anions

• Published in: Electrochimica acta Vol. 325; p. 134914
• Main Authors: Ramirez, Patricio, Manzanares, José A., Cervera, Javier, Gomez, Vicente, Ali, Mubarak, Nasir, Saima, Ensinger, Wolfgang, Mafe, Salvador
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.12.2019; Elsevier BV
• Subjects: Calcium ions; Conductance minima; Divalent cations; Divalent ions; Electrolytes; Functionalized conical nanopore; Ion exchange; Organic chemistry; Porosity; Resistance; Selectivity; Surface charge; Surface charge regulation; Surface charge regulation; Functionalized conical nanopore; Conductance minima; Divalent ions
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2019.134914

The surface charge regulation in nanoscale volumes is a subject of wide interest to biological and chemical soft matter systems. Also, electrolyte mixtures with monovalent and divalent ions are commonplace in practical applications with micro and nanoporous ion-exchange membranes. We have studied experimentally and theoretically the conductance of conical nanopores functionalized with negative and positive surface charges that are bathed by electrolyte mixtures of the monovalent ions K+ and Cl− and the divalent ions Mg2+, Ba2+, Ca2+, and SO42−. Small concentrations of these ions can modulate the nanopore selectivity and conductance because of their interaction with the charged groups on the pore surface. We have also given a qualitative description of the surface charge regulation using a simplified model for multivalent ion mixtures. Surface charge regulation of nanopore conductance by divalent ions. [Display omitted]