Electrical Double Layer Properties of Spherical Oxide Nanoparticles

TL;DR

This paper investigates how pH and nanoparticle size influence the electrical double layer properties of spherical oxide nanoparticles using classical solvation density functional theory and surface complexation models.

Contribution

It introduces a combined theoretical approach to analyze the effects of pH and size on nanoparticle electrostatics and ion distributions.

Findings

Rich, non-trivial ion density profiles observed

Electrostatic potential behavior varies with pH and size

Dominant interactions identified for ionic driving force

Abstract

The accurate characterization of electrical double layer properties of nanoparticles is of fundamental importance for optimizing their physicochemical properties for specific biotechnological and biomedical applications. In this article, we use classical solvation density functional theory and a surface complexation model to investigate the effects of pH and nanoparticle size on the structural and electrostatic properties of an electrolyte solution surrounding a spherical silica oxide nanoparticle. The formulation has been particularly useful for identifying dominant interactions governing the ionic driving force under a variety of pH levels and nanoparticle sizes. As a result of the energetic interplay displayed between electrostatic potential, ion-ion correlation and particle crowding effects on the nanoparticle surface titration, rich, non-trivial ion density profiles and mean electrostatic potential behavior have been found.