Investigation of Hydrolysis and Condensation in Organically Modified Sol-Gel Systems: 29SI NMR and the INEPT Sequence

1996 ◽  
Vol 435 ◽  
Author(s):  
T. M. Alam ◽  
R. A. Assink ◽  
D. A. Loy
Keyword(s):  
Sol Gel ◽  
29Si Nmr ◽  
Hydrolysis And Condensation ◽  
Organically Modified

Studies of the Initial Steps in Sol-Gel Processing of Si(OR)4:29Si NMR of Alkoxysilane and Alkoxysiloxane Solutions

1986 ◽  
Vol 73 ◽  
Author(s):  
Carol A. Balfe ◽  
Sheryl L. Martinez
Keyword(s):  
Aqueous Solution ◽  
Acid Catalysis ◽  
Chemical Shifts ◽  
Sol Gel ◽  
29Si Nmr ◽  
Methanol Solutions ◽  
Hydrolysis And Condensation ◽  
Silicic Acids ◽  
Starting Solutions ◽  
Gel Processing

ABSTRACTSilicon-29 NMR has been used to investigate the initial steps of hydrolysis and condensation of tetramethoxysilane (TMOS), hexamethoxydisiloxane, and octamethoxytrisiloxane in both basic and acidic methanol solutions. Comparisons of the spectra obtained from the various starting solutions and literature reports of mono-, di-, and tri-silicic acids in aqueous solution were used to identify and assign chemical shifts to condensation intermediates in the TMOS system. The observation of cyclic intermediates in the acid catalysis of TMOS in methanol and the chemical shifts of several products of its hydrolysis and condensation are reported.

scholarly journals FLUORESCENCE STUDIES FOR IN SITU MONITORING OF THE HYDROLYSIS AND POLYMERIZATION REACTIONS OF ORGANICALLY –MODIFIED TETRAMETHYLORTHOSILICATE

2010 ◽  
Vol 5 (3) ◽  
pp. 290-294
Author(s):  
Eko Sri Kunarti
Keyword(s):  
Condensation Reaction ◽  
Sol Gel ◽  
In Situ Monitoring ◽  
Condensation Polymerization ◽  
Surrounding Water ◽  
Fluorescence Studies ◽  
Hydrolysis And Condensation ◽  
Organically Modified ◽  
Kinetics Of

Monitoring of hydrolysis and condensation polymerization reactions of tetramethylorthosilicate-organosiloxane have been carried out. Proton transfer from the excited state of 8-hydroxy-1,3,6-pyrenetrisulfonic acid trisodium salt (pyranine) to surrounding water molecules was used as a sensitive fluorescence method for following the kinetics of water consumption during the early stages of the sol-gel polymerisation process. Changes in water/silane ratio, type of organosiloxane, mol ratio of organosiloxane to silica precursor and pH affected markedly the kinetic behavior of the hydrolysis and condensation reaction of tetramethylorthosilicate.   Keywords: hydrolysis, polymerisation, fluorescence, pyranine, tetramethylorthosilicate, organosiloxane.

Microstructural characterization of sol-gel coating on PET films

1994 ◽  
Vol 52 ◽  
pp. 886-887
Author(s):  
R. T. Chen ◽  
R.A. Norwood
Keyword(s):  
Ion Beam ◽  
Sol Gel ◽  
Industrial Applications ◽  
Hard Coatings ◽  
Nanometer Scale ◽  
Ion Beam Sputtering ◽  
Process Technology ◽  
Refractive Index Measurement ◽  
Organically Modified ◽  
Pet Films

Sol-gel processing has been used to control the structure of a material on a nanometer scale in preparing advanced ceramics and glasses. Film coating using the sol-gel process was also found to be a viable process technology in applications such as optical, porous, antireflection and hard coatings. In this study, organically modified silicate (Ormosil) coatings are applied to PET films for various industrial applications. Sol-gel materials are known to exhibit nanometer scale structures which havepreviously been characterized by small-angle X-ray scattering (SAXS), neutron scattering and light scattering. Imaging of the ultrafine sol-gel structures has also been performed using an ultrahigh resolution replica/TEM technique. The objective of this study was to evaluate the ultrafine structures inthe sol gel coatings using a direct imaging technique: atomic force microscopy (AFM). In addition, correlation of microstructures with processing parameters, coating density and other physical properties will be discussed.The materials evaluated are organically modified silicate coatings on PET film substrates. Refractive index measurement by the prism coupling method was used to assess density of the sol-gel coating.AFM imaging was performed on a Nanoscope III AFM (by Digital Instruments) using constant force mode. Solgel coating samples coated with a thin layer of Ft (by ion beam sputtering) were also examined by STM in order to confirm the structures observed in the contact type AFM. In addition, to compare the previous results, sol-gel powder samples were also prepared by ultrasonication followed by Pt/Au shadowing and examined using a JEOL 100CX TEM.

Liquid state 29Si NMR study on the sol-gel reaction mechanisms of ormosils

1993 ◽  
Vol 159 (1-2) ◽  
pp. 65-72 ◽  
Author(s):  
Takashi Iwamoto ◽  
Kazuki Morita ◽  
John D. Mackenzie
Keyword(s):  
Reaction Mechanisms ◽  
Liquid State ◽  
Sol Gel ◽  
29Si Nmr ◽  
Nmr Study

Preparation of Porous Organically-Modified Silicate Hybrids for Cell Culture Matrix

2007 ◽  
Vol 330-332 ◽  
pp. 1177-1180 ◽  
Author(s):  
Kanji Tsuru ◽  
Satoshi Hayakawa ◽  
Yuki Shirosaki ◽  
T. Okayama ◽  
K. Kataoka ◽  
...  
Keyword(s):  
Cell Culture ◽  
Mammalian Cells ◽  
Pore Diameter ◽  
Sol Gel ◽  
Three Dimensional ◽  
Culture Methods ◽  
Organically Modified ◽  
Dimensional Cell

Porous & rubbery organic-inorganic hybrids were synthesized from tetraethoxysilane (TEOS) and polydimethylsiloxane (PDMS) through a sol-gel route using sieved sucrose granules as a porogen. The porous hybrids with a high content of PDMS behaved like polymer sponge. The porosity was over 90% irrespective of the hybrid composition and the pore diameter ranged from 100 to 500 μm. In the three-dimensional cell culture, mammalian cells were well cultured in the porous hybrids. The present results indicate that the hybrids may be a promising scaffold for developing such functional culture methods.

scholarly journals Inorganic-Organic Composites (Ormocers) as Structured Layers for Microelectronics

1990 ◽  
Vol 180 ◽  
Author(s):  
Michael Popall ◽  
Henning Meyer ◽  
Helmut Schmidt ◽  
Jochen Schulz
Keyword(s):  
System Integration ◽  
Signal Transmission ◽  
Sol Gel ◽  
Unsaturated Hydrocarbon ◽  
Direct Laser ◽  
Organically Modified ◽  
Integration Techniques ◽  
Edge Quality ◽  
Low Permittivity ◽  
High Bulk

ABSTRACTEnhanced integration, faster signal transmission and reduced size of mounting devices in components for microelectronics requires new patternable materials. Inorganic-organic copolymers (ORMOCERs = ORganically MOdified CERamics), prepared by sol-gel techniques have been developed for interconnection technologies in microelectronics. Photopolymerization is enabled by unsaturated hydrocarbon or epoxide substituents and UV-sensitive initiators. Using a frequency doubled Argonion laser at 257 nm for direct laser writing, patterned layers with high edge quality have been realized. In combination with high breakthrough voltages, low permittivity constants and high bulk resistivities they open interesting aspects for very large system integration techniques (VLSI).

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