Solid-state silicon-29 and carbon-13 NMR spectroscopy using cross-polarization and magic-angle-spinning techniques to characterize 3-chloropropyl and 3-aminopropyl-modified silica gels

Sudhölter, Ernst J. R.; Huis, R.; Hays, Gary R.; Alma, N.C.M.

doi:10.1016/0021-9797(85)90130-4

Cited by 94 publications

(50 citation statements)

References 17 publications

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“…2b, only the more condensed silicon atoms of the coupling agent and silica core can be recognized (T' at 60.5 ppm, T3 at 65.7 ppm, Q 3 at 102.4 ppm, and Q4 at 110.4 ppm) . These chemical shift values of the different silicon atoms are in agreement with literature values found for APS-modified silica ( 17,18,43 ) and were also found for the organo-silica spheres Mix 1.…”

Section: Puuticle Compositionsupporting

confidence: 91%

Synthesis and Characterization of Monodisperse Colloidal Organo-silica Spheres

Blaaderen

Vrij

1993

Journal of Colloid and Interface Science

414

349

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Monodisperse, colloidal silica spheres were prepared from tetraethoxysilane (TES) in mixtures of ammonia, water, and ethanol. The surface of the particles could be coated through a subsequent chemical reaction with the silane coupling agent 3-aminopropyltriethoxysilane (APS). Also, a new kind of monodisperse, colloidal silica spheres (organo-silica spheres) was prepared starting from mixtures of APS and TES. Organo-silica spheres synthesized with equal amounts of APS and TES were found to contain as much as 37% of the total amount of APS. The amount taken up by the particles, and therefore also the particle properties, depended on the initial composition of the mixture of alkoxides. It is argued that the most important reaction by which APS is incorporated into the particles is through an alcohol-producing condensation reaction with a silanol group bonded to a silicon atom that was part of a TES molecule. Because of this proposed mechanism, it is argued that this basecatalyzed method of making hybrid organic-silica particles will also be applicable to mixtures of other organoalkoxides. The organo-silica spheres differed from silica spheres prepared with TES alone in the following aspects: The negative surface charge in the mixture of water, ammonia and ethanol was reduced, the mass density was lower (e.g., 1.51 g/cm3 compared to 1.98 g/cm3), the microporosity was larger, and the siloxane structure was less condensed. The particle refractive index was higher, but the differences were small (around 0.02). It was shown that particles with APS on the surface could be grown larger with a silica layer prepared from TES. Organo-silica particles and silicacoated organo-silica particles were surface coated with stearyl alcohol. The resulting stability in several solvents was assessed. The different colloidal systems were characterized by static and dynamic light scattering, transmission electron microscopy, elemental analysis, nitrogen adsorption measurements, electrophoresis, and qualitative r3C and quantitative r9Si solid-state nuclear magnetic resonance spectroscopy. 8

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Section: Puuticle Compositionsupporting

confidence: 91%

Synthesis and Characterization of Monodisperse Colloidal Organo-silica Spheres

Blaaderen

Vrij

1993

Journal of Colloid and Interface Science

414

349

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“…The 29 Si NMR spectra ( 1 H coupling and decoupling) in each step match well with data reported previously [59].…”

Section: Functionalization Of Mcm-41supporting

confidence: 87%

MCM-41-supported platinum carbonyl cluster-derived catalysts for asymmetric and nonasymmetric hydrogenation reactions

Basu

Mapa

Gopinath

et al. 2006

Journal of Catalysis

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“…7,8,[14][15][16][17][18] The short backbone alkyl chains (three -CH 2 ) of APTES provide insufficient intermolecular van der Waals forces to form an ordered monolayer, instead forming a disordered loose three-dimensional multilayered network that anchors to the substrate with fewer chemical bonds. 7,[17][18][19][20] This loose network allows the interdiffusion of a) Electronic mail: bimin@uakron.edu polymer chains, especially for polymers that are compatible with APTES. The network can be tightened when the APTES molecules cross-link with each other under thermal annealing to firmly lock the diffused polymer chains in the network.…”

Section: Introductionmentioning

confidence: 99%

Retention of poly(N-isopropylacrylamide) on 3-aminopropyltriethoxysilane

et al. 2017

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Silane coupling agents are commonly employed to link an organic polymer to an inorganic substrate. One of the widely utilized coupling agents is 3-aminopropyltriethoxy silane (APTES). In this study, the authors investigated the ability of APTES to retain thermo-responsive poly(N-isopropylacrylamide) (pNIPAAm) on hydroxylated surfaces such as glass. For comparison purposes, the authors also evaluated the retention behaviors of (1) polystyrene, which likely has weaker van der Waals interactions and acid-base interactions (contributed by hydrogen-bonding) with APTES, on APTES as well as (2) pNIPAAm on two other silane coupling agents, which have similar structures to APTES, but exhibit less interaction with pNIPAAm. Under our processing conditions, the stronger interactions, particularly hydrogen bonding, between pNIPAAm and APTES were found to contribute substantially to the retention of pNIPAAm on the APTES modified surface, especially on the cured APTES layer when the interpenetration was minimal or nonexistent. On the noncured APTES layer, the formation of an APTES-pNIPAAm interpenetrating network resulted in the retention of thicker pNIPAAm films. As demonstrated by water contact angles [i.e., 7 -15 higher at 40 C, the temperature above the lower critical solution temperature (LCST) of 32 C for pNIPAAm, as compared to those at 25 C] and cell attachment and detachment behaviors (i.e., attached/spread at 37 C, above LCST; detached at 20 C, below LCST), the retained pNIPAAm layer (6-15 nm), on both noncured and cured APTES, exhibited thermo-responsive behavior. The results in this study illustrate the simplicity of using the coupling/adhesion promoting ability of APTES to retain pNIPAAm films on hydroxylated substrates, which exhibit faster cell sheet detachment ( 30 min) as compared to pNIPAAm brushes (in hours) prepared using tedious and costly grafting approaches. The use of adhesion promoters to retain pNIPAAm provides an affordable alternative to current thermo-responsive supports for cell sheet engineering and stem cell therapy applications.

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Solid-state silicon-29 and carbon-13 NMR spectroscopy using cross-polarization and magic-angle-spinning techniques to characterize 3-chloropropyl and 3-aminopropyl-modified silica gels

Cited by 94 publications

References 17 publications

Synthesis and Characterization of Monodisperse Colloidal Organo-silica Spheres

Synthesis and Characterization of Monodisperse Colloidal Organo-silica Spheres

MCM-41-supported platinum carbonyl cluster-derived catalysts for asymmetric and nonasymmetric hydrogenation reactions

Retention of poly(N-isopropylacrylamide) on 3-aminopropyltriethoxysilane

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