Dielectric discontinuity effects on the adsorption of a linear polyelectrolyte at the surface of a neutral nanoparticle

Abstract

The formation of complexes between nanoparticles and polyelectrolytes is a key process for the control of the reactivity of manufactured nanoparticles and rational design of core shell nanostructures. In this work, we investigate the influence of the nanoparticle dielectric constant on the adsorption of a linear charged polymer ͑polyelectrolyte͒ at the surface of a neutral nanoparticle. The polyelectrolyte linear charge density, as well as the image charges in the nanoparticle due to the dielectric discontinuity, is taken into account. Monte Carlo simulations are used to predict the adsorption/desorption limits and system properties. Effects of the nanoparticle size and polyelectrolyte length are also investigated. The polyelectrolyte is found adsorbed on the nanoparticle when the dielectric constant of the nanoparticle is greater than the dielectric constant of the medium. Attractive interactions induced by the presence of opposite sign image charges are found strong enough to adsorb the polyelectrolyte showing that the reaction field contribution has to be considered. The affinity between the polyelectrolyte and the nanoparticle is found to increase in magnitude by increasing the nanoparticle size and dielectric constant. The reaction field magnitude is also found to depend in a nonlinear way from the polyelectrolyte length.

Effects of the dielectric discontinuity on the counterion distribution in a colloidal suspension

“…Polarization effects have also been explored in ionic liquids [25][26][27][28] and for polyelectrolyte adsorption [29][30][31] in a slab geometry. In this paper we will derive the explicit inter-ionic interaction potential which very accurately accounts for the dielectric discontinuity for spherical colloidal particles.…”

Polyelectrolyte adsorption onto oppositely charged interfaces: unified approach for plane, cylinder, and sphere

“…This generates a short-range PE-surface repulsion (for a plane, e.g., the image forces have half as short screening length compared to direct Debye-Hu¨ckel PE-surface attraction). The adsorbed PEs are thus effectively ''pushed aside'' from the surface 72 and generally larger surface charge densities are required for PE-surface adsorption. 73 One biological application of such image-force effects is the complexation of flexible single-stranded nucleic acid chains on the interior of capsid shells of many single-stranded RNA/DNA viruses, 74,75 both of spherical and filamentous appearance.…”

Strategies for determining heteroaggregation attachment efficiencies of engineered nanoparticles in aquatic environments

“…18 The DLVO theory has been extended to include additional interactions, 39,40 e.g. hydrogen bonding, hydration pressure, Lewis acid base interactions, charge regulations, image charge effects 41 or steric effects, which can be particularly relevant for particles in the nano-range.…”