Chemical and Biological Engineering ETDs

Publication Date

Fall 12-15-2019

Abstract

The physical origin of charged interfaces involving electrolyte solutions is in the thermodynamic equilibrium between the surface reactive groups and certain dissolved ionic species in the bulk. This equilibrium is very strongly dependent on the precise local density of these species, also known as potential determining ions in the solution. The latter, however, is determined by the overall solution structure, which is dominated by the large number of solvent molecules relative to all solutes. Hence, the solvent contribution to the molecular structure is a crucial factor that determines the properties of electric double layers. Models that explicitly account for the solvent structure are often referred to as "civilized" as opposed to the "primitive" ones that consider the solvent as a structureless continuum. A physically correct description of charged interfaces that involve electrolyte solutions (electric double layers), needs to account for the full solution structure in conjunction with the precise surface chemistry governed by the thermodynamic equilibrium.

Apart from charge regulation, these systems involve a wide variety of interactions between the different components of the electrolyte solutions and with the charged interface. While the role of all Coulombic type of interactions is clear, that of the non-Coulombic forces is less obvious. Such as the effects of bulk solvation interactions and solvophobic or solvophillic interactions on the properties of the electric double layer.

This doctoral dissertation presents a comprehensive study of the effects of the non-electrostatic interactions on the electric double layer such as ionic solvation, solvent-solvent interactions and interactions of solution components with the charged surface in Electric double layer. The analysis of electrostatic properties like surface charge and potential, and the distribution of ionic species and total electrostatic charge distribution were presented. The analysis uses classical Density Functional Theory which treats the solvent explicitly and ionic species with finite sizes coupled with surface charge regulation.

Keywords

Electric Double Layers, Colloids, Interfaces, DLVO, forces, classical DFT, Density functional theory

Document Type

Dissertation

Language

English

Degree Name

Chemical Engineering

Level of Degree

Doctoral

Department Name

Chemical and Biological Engineering

First Committee Member (Chair)

DIMITER N PETSEV

Second Committee Member

FRANK VAN SWOL

Third Committee Member

FERNANDO GARZON

Fourth Committee Member

JOSE M CERRATO

Fifth Committee Member

BOIAN S ALEXANDROV

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