Silanation of silica surfaces. A new method of constructing pure or mixed monolayers

Abstract

We present a quantitative study of different parameters of the silanation reaction (grafting of long aliphatic chains on silica surfaces via trichlorosilane group). Some of them, such as temperature or water traces, are shown to be particularly crucial. A mechanism for the reaction, completing the one previously reported, is proposed and optimal experimental conditions to perform high-quality monolayers of long aliphatic chains are deduced. Characterizations were performed with different techniques including X-ray reflectivity experiments and contact angle measurements. Results are consistent with well organized layers in which the chains are densely packed completely extended perpendicular to the surface. In the case of mixtures, the layer comportment reflects the concentration of each species in solution; there does not seem to be any segregation.

The molecular level modification of surfaces: from self-assembled monolayers to complex molecular assemblies

“…3), 31 or physically adsorbed silane molecule on the SiO 2 surface. 38 It is however, very difficult to distinguish physically adsorbed silanes from chemically conjugated SAM molecules. For many applications, whether a monolayer, or rather an ill-defined multilayer is formed, is not a significant issue.…”

Development and characterization of polymer-grafted ceramic membranes for solvent nanofiltration

“…SRNF membranes show a high potential in chemical synthesis as the recovery of homogeneous catalysts from reaction products [93] [94][95][96][97][98]. Many of the reactions where these catalysts are used are performed in solvents, resulting in extensive and usually destructive separations.…”

“…SRNF has also been applied in this sector for other applications e.g. the recovery of organometallic complexes [99] from organic solvents and separation of phase transfer catalysts (PTC) from toluene [94,100,101]. In contrast to homogeneous catalyst separation, separations in petrochemical applications are often between compounds, which have very similar molecular properties.…”

Xerogel p-anisidinapropilsílica: estudo da estabilidade térmica e da resistência à lixiviação com solventes

“…Um método bastante utilizado na imobilização de grupos orgâ-nicos sobre sílica é o enxerto 1,[4][5][6] . Nesse método é comum usar-se um organosilano de fórmula R-Si(OCH 3 ) 3 , sendo R um grupo orgânico alifático, aromático ou ainda cadeia orgânica contendo outros grupos funcionais.…”