Adsorbed behavior of spin‐labeled silane coupling agent on colloidal silica studied by electron spin resonance

Abstract
The adsorption mechanism of silane coupling agent on the colloidal silica surface is studied with spm-labeled silane coupling agent using ESR method. The density of the adsorbed silane molecules was determined to be approximately 1.5–2 molecules per 100 Å2 of the silica surface in 95% ethanol solution. In addition, ESR signal of spin-labeled agent adsorbed on the colloidal silica surface was composed of two components; slow component attributable to the agents adsorbed directly on the SiOH groups of the silica surface through hydrogen bond formation and rapid one attributable to the agents interacted with such adsorbed silane molecules.