Substituent Effects on the Sol−Gel Chemistry of Organotrialkoxysilanes

Abstract

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Favourable influence of hydrophobic surfaces on protein structure in porous organically-modified silica glasses

“…BET measurements indicate that all five alkyl precursors have a comparable effect on the glass, independent of chain length; surface area is increased and pore volume is decreased to a similar extent for all modified glasses relative to the unmodified glass (Table 1). This result is consistent with the formation of smaller silica particles prior to gelation due to a preponderance of reaction-terminating alkylsilane groups on the surface of the growing particle; at much higher concentrations of the alkyltrimethoxysilane precursor, phase separation can lead to the formation of crystalline oligomers, resinous materials, and precipitates [47].…”

Solid-state 29Si NMR and FTIR analyses of lignin-silica coprecipitates

“…Si NMR spectra do not show any other major shift, probably because the formation of covalent bonds, if any, are below the detection limit (Loy et al 2000). ATR-FTIR spectra of the coprecipitates exhibited characteristic bands at 1200-1000 cm -1 and at 850-750 cm -1 positioned at higher frequency than in the case of the silica sample (Figure 7).…”

Porosity in Polysilsesquioxane Xerogels

“…' While there is extensive information on the formation of polysilsesquioxanes, ' there has not been a survey of the ability of organotrialkoxy silanes to form gels until recently. 4…”