Bjerrum pairing correlations at charged interfaces

TL;DR

This paper investigates electrostatic correlations at charged interfaces, distinguishing two regimes, and develops a first-principles theory for Bjerrum pairing that aligns well with experimental data.

Contribution

It introduces a theoretical framework for transverse correlations leading to Bjerrum pairing at charged interfaces, validated by experimental comparisons.

Findings

Good agreement between theory and experiments on membranes and monolayers.

Identification of mutually exclusive correlation regimes at charged interfaces.

Theoretical prediction of binding constants from first principles.

Abstract

Electrostatic correlations play a fundamental role in aqueous solutions. In this letter, we identify transverse and lateral correlations as two mutually exclusive regimes. We show that the transverse regime leads to binding by generalization of Bjerrum pair formation theory, yielding binding constants from first-principle statistical-mechanical calculations. We compare our theoretical predictions with experiments on charged membranes and Langmuir monolayers and find good agreement. We contrast our approach with existing theories in the strong-coupling limit and on charged modulated interfaces, and discuss different scenarios that lead to charge reversal and equal-sign attraction by macro-ions.