Abstract
SynopsisThe surface treatment of spherical silica particles using mixed silane coupling agents having di- and trialkoxy groups was carried out, and the molecular mobility of treated layer was analyzed using a 1H pulse NMR. The silane coupling agents used in this study have mercapto group as a functional group. In order to vary the amount of adsorbed silane on particle surface, the amount of silane added at surface treatment was set in the range from 1.5 to 7 times larger than that required for monolayer coverage. The relaxation time measured on the surface layer by a pulse NMR was longer for the dialkoxy structure than the trialkoxy structure. The relaxation time measured for the mixed silane-treated system increased with an increase of the dialkoxy silane content in the range of those for the dialkoxy and the trialkoxy structures. The tendency became more remarkable with an increase of the amount of adsorbed silane.
