Infrared Method for In Situ Studies of Polymer/Surfactant Adsorption on Silica Powders from Aqueous Solution

Abstract

This article presents a general infrared spectroscopic method that enables the monitoring of the adsorption of surfactants and poly-electrolytes on high surface area silica particles from aqueous solution. The method is based on the use of a ZnSe internal reflection element (IRE) coated with a layer of titania particles. The titania surface is then converted to silica using atomic layer deposition with sequential addition of an amine catalyst, gaseous SiCl₄, and water vapor. A minimum of three cycles is needed to produce a surface that mimics silica, as evidenced by the reaction of hexamethyldisilazane and zeta potential measurements. It is shown that the silica-coated titania particles on the ZnSe crystals are stable to flowing aqueous solutions below pH = 8 and can be used to study the dynamics of polymer/surfactant adsorption on silica.