Comparison of Techniques for Measuring the Electrical Double Layer Properties of Surfaces in Aqueous Solution: Hexadecyltrimethylammonium Bromide Self-Assembly Structures as a Model System

Abstract

The effect of aqueous KBr concentration on the electrical double layer properties of two types of self-assembled hexadecyltrimethylammonium bromide (CTAB) surfaces has been investigated. A solvatochromic acid-base indicator has been used to determine the surface potential (Φ0) of CTAB micelles. Three different techniques have been employed to examine self-assembled CTAB bilayers adsorbed on amorphous silica surfaces. Flat plate streaming potentials (ζs potentials), electrostatic potentials obtained from the electrophoretic mobility of relatively large colloid spheres (ζe potentials), and diffuse layer potentials (ipa) derived from the force versus separation curvss for the interaction of a c..