Electrostatics at the interface

1/19/01


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Table of Contents

Electrostatics at the interface

Coulomb’s law

Gauss’s law

Potential due to a charged sphere

Poisson equation

Charge redistribution at phase boundaries

Electrode double layer: Gouy-Chapman Theory

Ion concentration in the double layer

Space charge density due to ions near charged surfaces

Debye-Huckel Theory

Significance of the Debye length

Application of Debye-Huckel

Colloids are mutually repelled by electrostatic forces

Double layer at a colloid

The potential near a colloid

Calculating V0

Colloids are mutually attracted by dispersive forces

The multipole expansion

London Dispersion Forces

The induced dipole term

Hamaker Theory

Superposition of forces

Calculated potential curves for 10 nm gold colloids

Author: Stefan Franzen