Effects of Surface Modification on Adsorption Phenomena

Nuclear Magnetic Resonance Studies of Interfacial Phenomena 

FIGURE 1.132 Si CP/MAS NMR spectra of (a) modified nanosilica A-200 with different amounts of grafted trimethylsiloxane groups and (b) Zorbax octadecyl RP-HPLC phases with (1) diisobutyl-n-octadecylsiloxane and (2) dimethyl-n-octadecylsiloxane. (Adapted from J. Chromatography A., 688, Scholten, A.B., de Haan, J.W., Claessens, H.A., van der Ven, and Cramers, C.A., 29-Silicon NMR evidence 

FIGURE 1.134 H NMR spectra (1) obtained for the original linear cationic poly(acrylamide-co-2-(dimethylamino) ethyl methacrylate, methyl chloride quatemized) (poly(AM-co-DMC)) with 30 mol% of DMC and (2) obtained for the hybrid copolymer-silica nanoparticles. (Adapted from J. Colloid Interface Sci., 338, Li, X., Yang, T., Gao, Q., Yuan, J., and Cheng, S., Biomimetic synthesis of copolymer-silica nanoparticles with tunable compositions and surface property, 99-104, 2009b. Copyright 2009, with permission from Elsevier.) 

Mijatovic et al. (2000) stndied nnmodified and silane-modified nanosilica (5bet=200 m /g) using 2 Si solid-state NMR spectroscopy. The mode of bonding onto the silanol surface (mono- or divalent, seven different surface functionalities) was specified by comparison with chemical shifts from solution. A detailed analysis was performed with respect to products formed via hydrosilylation reactions using a rough quantification of the snrface loading with a signal deconvolution process of the silanol resonances on the Aerosil snrface. Thns, the NMR techniques were mainly used to analyze the chemical structure of whole silica materials or their surface. 

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