We study the structural characteristics of a system of charged nanoparticles in a neutral polymer solution while accounting for the differences in the dielectric constant between the particles, polymer and the solvent. We use a hybrid computational methodology involving a combination of single chain in mean-field simulations and the solution of the Poisson's equation for the electrostatic field. We quantify the resulting particle structural features in terms of radial distribution function among particles as a function of the dielectric contrast, particle charge, particle volume fraction and polymer concentration. In the absence of polymers, charged macroions experience increased repulsion with a lowering of the ratio of particle to solvent dielectric constant. The influence of the dielectric contrast between the particle and the solvent however diminishes with an increase in the particle volume fraction and/or its charge. In the presence of neutral polymers, similar effects manifest, but with the additional physics arising from the fact that the polymer-induced interactions are influenced by the dielectric contrast of the particle and solvent.
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Multiparticle orientational correlations are responsible for the nonlinear dielectric effect: Analysis of temperature-dependent measurements for glycerol
The nonlinear dielectric effect (NDE) is traditionally viewed as originating from saturation of the response of individual dipoles in a strong electric field. This mean-field view, mathematically described by the Langevin saturation function, predicts enhanced dielectric saturation at lower temperatures. In contrast, recent experiments for glycerol have shown a sharp increase of the NDE with increasing temperature. The formalism presented here splits the NDE into a sum of a term representing binary correlations of dipolar orientations and terms referring to three- and four-particle orientational correlations. Analysis of experimental data shows that the contribution of three- and four-particle correlations strongly increases at elevated temperatures. The mean-field picture of dielectric saturation as the origin of the NDE is inconsistent with observations. A positive NDE (increment of the field-dependent dielectric constant) is predicted for low-concentration solutions of polar molecules in nonpolar solvents. The dependence of the NDE on the concentration of the polar component is polynomial.
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- Award ID(s):
- 2154465
- PAR ID:
- 10399489
- Date Published:
- Journal Name:
- The Journal of Chemical Physics
- Volume:
- 157
- Issue:
- 16
- ISSN:
- 0021-9606
- Page Range / eLocation ID:
- 164501
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1063/5.0106766
