Measuring surface charge: why experimental characterization and molecular modeling should be coupled

TL;DR

This paper emphasizes the importance of integrating experimental techniques with molecular modeling to accurately characterize surface charge distributions and dynamics at liquid-solid interfaces, addressing limitations of individual methods.

Contribution

It advocates for coupling experimental approaches with molecular simulations to overcome current limitations in surface charge measurement and understanding.

Findings

Experimental methods provide local structural and transport information.

Molecular dynamics simulations reveal model limitations and guide improvements.

Coupling both approaches enhances understanding of charged interfaces.

Abstract

Surface charge controls many static and dynamic properties of soft matter and micro/nanofluidic systems, but its unambiguous measurement forms a challenge. Standard characterization methods typically probe an effective surface charge, which provides limited insight into the distribution and dynamics of charge across the interface, and which cannot predict consistently all surface-charge-governed properties. New experimental approaches provide local information on both structure and transport, but models are typically required to interpret raw data. Conversely, molecular dynamics simulations have helped showing the limits of standard models and developing more accurate ones, but their reliability is limited by the empirical interaction potentials they are usually based on. This review highlights recent developments and limitations in both experimental and computational research focusing on the liquid-solid interface. Based on recent studies, we make the case that coupling of experiments and simulations is pivotal tomitigate methodological shortcomings and address open problems pertaining to charged interfaces.