A preliminary study of the relation between adsorption and CP-MAS-NMR characteristics of fused silica model substrates

The fumed silica model substrate Aerosil was trimethylsilylated to different extents and studied by the combination of IGC and 29Si CP-MAS-NMR. Dihydroxydisiloxane groups were shown to be chemically more reactive than monohydroxytrisiloxane groups. Chromatographic experiments showed that these groups play an important role in the adsorption of functionalized solutes. Apart from the lowering of the surf ace energy of the Aerosil phases, also the types and the magnitudes of the specific interactions of test components with residual silanols could be studied. It was shown that IGC gives complementary information on the physico-chemical nature of the chemical surface structures identified by 29Si CP-MAS-NMR