Silicon-29 and carbon-13 NMR characterization of mixed horizontally polymerized monolayers on silica gel

摘要: A horizontally polymerized monolayer of mixed C[sub 18] and 3] trifunctional silanes on silica, conventional chromatographic phases, are studied by NMR spectroscopy. For horizontal polymerization, quantitative [sup 13]C 29]Si measurements reveal that a dense highly bonded groups is formed the surface. The polymeric surface, contrast, oligomeric in nature: ratio to reacted substrate silanols only slightly more than 1:1, average oligomer size 5 units. data insignificant vertical polymerization. show chain dynamics for similar those monomeric monolayer, whereas phase significantly slower. These results indicate chains randomly interspersed with short phase. 31 refs., figs., 4 tabs.