arXiv subjects

Petr E. Brandyshev

Publications and source records attributed to Petr E. Brandyshev.

4 recordsLinked to original sources

arXiv2025

Osmolyte-Modulated Differential Capacitance and Disjoining Pressure for Nanoconfined Electrolytes: A Modified Poisson-Boltzmann Theory

This study employs modified Poisson-Boltzmann theory to systematically investigate the influence of zwitterionic osmolyte additives to an electrolyte solution on disjoining pressure and electric differential capacitance within charged slit-like nanopores with conductive walls. We demonstrate that increasing concentrations of zwitterionic osmolytes synergistically enhance both disjoining pressure and differential capacitance, highlighting their dual role in the potential improvement of supercapacitor performance. The insights gained underscore the unique capabilities of zwitterionic osmolytes as multifunctional additives for fine-tuning the properties of electric double layers, thereby bridging the gap between capacitive efficiency and microporous electrode longevity.

cond-mat.soft↗

arXiv2025

A Fluctuation Theory of Liquid-Phase Solutions: Shear Viscosity

Accurately describing liquids and their mixtures beyond equilibrium remains a significant challenge in modern chemical physics and physical chemistry, especially regarding the calculation of transport properties in liquid-phase systems. This paper introduces a phenomenological nonequilibrium theory specifically designed for multicomponent liquid-phase solutions. Our field-theoretical framework, rooted in nonequilibrium statistical mechanics, incorporates quasi-stationary concentration fluctuations that align with equilibrium liquid theory as described by classical density functional theory. This method serves as a phenomenological extension of the established Dean-Kawasaki stochastic density functional theory, enabling the computation of shear viscosity. We apply our approach to derive general formula for the shear viscosity in single-solute solutions. Our findings yield new results and successfully reproduce previously established results for such systems as solutions containing soft-core particles, hard spheres, one-component plasma, and near-critical solutions.

cond-mat.soft↗

arXiv2024

Variational field theory of macroscopic forces in Coulomb fluids

Based on the variational field theory framework, we extend our previous mean-field formalism, taking into account the electrostatic correlations of the ions. We employ a general covariant approach and derive a total stress tensor that considers the electrostatic correlations of ions. This is accomplished through an additional term that depends on the autocorrelation function of local electric field fluctuations. Utilizing the derived total stress tensor and applying the mechanical equilibrium condition, we establish a general expression for the disjoining pressure of the Coulomb fluids, confined in a pore with a slit-like geometry. Using this equation, we derive an asymptotic expression for the disjoining pressure in a slit-like pore with non-electrified conductive walls. Present theory is the basis for future modeling of the mechanical stresses that occur in electrode pores with conductive charged walls, immersed in liquid phase electrolytes beyond the mean-field theory.

cond-mat.soft↗

arXiv2024

Surface Tension of Aqueous Electrolyte Solutions. A Thermomechanical Approach

We determine the surface tension of aqueous electrolyte solutions in contact with non-polar dielectric media using a thermomechanical approach, which involves deriving the stress tensor from the thermodynamic potential of an inhomogeneous fluid. To obtain the surface tension, we calculate both the normal and tangential pressures using the components of the stress tensor, recently derived by us [Y. A. Budkov and P. E. Brandyshev, The Journal of Chemical Physics 159 (2023)] within the framework of Wang's variational field theory. Using this approach, we derive an analytical expression for the surface tension in the linear approximation. At low ionic concentrations, this expression represents the classical Onsager-Samaras limiting law. By utilizing only one fitting parameter, which is related to the affinity of anions to the dielectric boundary, we can approximate various experimental data regarding the surface tension of aqueous electrolyte solutions. This approximation applies to both the solution-air and solution-dodecane interfaces, covering a wide range of electrolyte concentrations.

cond-mat.soft↗