Macrocellular Silica Monoliths Hierarchically Textured: Mesostructured Si-HIPE Materials

2004 ◽  
Vol 847 ◽  
Author(s):  
F. Carn ◽  
A. Colin ◽  
R. Backov
Keyword(s):  
Soft Matter ◽  
Volume Fraction ◽  
Sol Gel ◽  
General Context ◽  
New Materials ◽  
Silica Monoliths ◽  
Sol Gel Process ◽  
Ph Conditions ◽  
Nice Tool ◽  
Concentrated Emulsion

ABSTRACTInterface between sol-gel process and soft matter appears recently as a very nice tool to generate new materials with complex textures or/and structures extended at various length scales. In this general context, hierarchical inorganic porous monoliths have been prepared using a double templates procedure, namely concentrated emulsion as a macroscopic pattern and mesoscopic micellar templates. The texture of those monoliths can vary dramatically playing either with the oil volume fraction, synthetic pH conditions or the emulsification process. These materials show interconnected macroporosity associated to vermicular-type mesostructuration with an average mesoporosity of 800 m2/g associated to bulk density as low as 0.08 g cm-3 which is comparable to values obtained for silica aerogel.

Sol-gel derived Ba(Mg1/3Ta2/3)O3 thin films: Preparation and structure

1997 ◽  
Vol 12 (3) ◽  
pp. 596-599 ◽  
Author(s):  
Ji Zhou ◽  
Qing-Xin Su ◽  
K. M. Moulding ◽  
D. J. Barber
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Small Grains

Ba(Mg1/3Ta2/3)O3 thin films were prepared by a sol-gel process involving the reaction of barium isopropoxide, tantalum ethoxide, and magnesium acetate in 2-methoxyethanol and subsequently hydrolysis, spin-coating, and heat treatment. Transmission electron microscopy, x-ray diffraction, and Raman spectroscopy were used for the characterization of the thin films. It was shown that the thin films tend to crystallize with small grains sized below 100 nm. Crystalline phase with cubic (disordered) perovskite structure was formed in the samples annealed at a very low temperature (below 500 °C), and well-crystallized thin films were obtained at 700 °C. Although disordered perovskite is dominant in the thin films annealed below 1000 °C, a low volume fraction of 1 : 2 ordering domains was found in the samples and grows with an increase of annealing temperature.

Self-encapsulation of a drug-containing ionic liquid into mesoporous silica monoliths or nanoparticles by a sol–gel process

RSC Advances ◽  
2016 ◽  
Vol 6 (86) ◽  
pp. 82916-82923 ◽  
Author(s):  
David Brevet ◽  
Claire Jouannin ◽  
Corine Tourné-Péteilh ◽  
Jean-Marie Devoisselle ◽  
André Vioux ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Mesoporous Silica ◽  
Sol Gel ◽  
Silica Monoliths ◽  
Templating Agent ◽  
Sol Gel Process

Mesoporous silica monoliths and nanospheres were obtained using the same ionic liquid acting as a templating agent and catalyst.

Spectroscopic Studies of Chemical Reactions and Dynamics in Sol-Gel Matrices

1994 ◽  
Vol 346 ◽  
Author(s):  
F. Akbarian ◽  
B. Dunnt ◽  
P.D. Fuquat ◽  
J. Mckiernan ◽  
E. Simoni ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Optical Materials ◽  
Copper Phthalocyanine ◽  
Sol Gel ◽  
Spectroscopic Studies ◽  
Pump Probe ◽  
Silica Monoliths ◽  
Sol Gel Process ◽  
Different Types ◽  
Gel Glasses

ABSTRACTThe synthesis of sol-gel glasses containing organic and organometallic molecular dopants has been well established as an approach for creating new optical materials. Some of these properties are dependent upon chemical reactions which occur in porous xerogel matrices during the sol-gel process or when encapsulated molecules are exposed to other molecules in solution. In this paper, the study of two different types of chemical reactions in the pores of xerogel matrices is reported. In one case copper phthalocyanine is used to characterize dimerization within the pores. The results show that dimer formation is most likely to occur towards the end of the drying stage as the dye concentration in the pores increases from solvent evaporation. A second example involves the use of a pump-probe technique to determine the rate of proton recombination inside the pores of silica monoliths. The behavior of sols and gels is similar to aqueous solution while recombination of protons in the xerogel seems to be affected by the walls of the pores.

Soft matter, sol–gel process and external magnetic field to design macrocellular silica scaffolds

2005 ◽  
Vol 263 (1-3) ◽  
pp. 341-346 ◽  
Author(s):  
Florent Carn ◽  
Annie Colin ◽  
Véronique Schmitt ◽  
Fernando Leal Calderon ◽  
Rénal Backov
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Soft Matter ◽  
Sol Gel ◽  
Sol Gel Process

Sol-Gel Networks: Fundamental Investigations of the Chemistry of Sol-Gel Silicate Glasses and Poly(Siloxane) Toughened Silicates

1989 ◽  
Vol 155 ◽  
Author(s):  
M. Spinu ◽  
J. E. Mcgrath
Keyword(s):  
Sol Gel ◽  
Processing Conditions ◽  
Organic Modifiers ◽  
New Materials ◽  
Reaction Parameters ◽  
Free System ◽  
Sol Gel Process ◽  
Subsequent Conversion ◽  
Strong Acids ◽  
Gel Network

ABSTRACTThe low-temperature sol-gel process opens a number of new materials possibilities for generation of glasses with predetermined properties by the incorporation of organic modifiers into the network. Polysiloxanes are potentially interesting organic modifiers for toughening and possibly surface-modifying the silicate networks. Some fundamental studies of the hydrolysis and condensation processes in a tetramethylorthosilicate (TMOS) system, in the absence of added catalyst, have been conducted using 1H and 29Si NMR. The effects of some of the reaction parameters and processing conditions for the subsequent conversion of the gel to monolithic dried gels by heat treatment have been investigated by techniques such as thermal analysis and mass spectroscopy. Procedures which employ mild pressures have been established that permit the generation of monolithic products which show greatly reduced cracking tendencies. Finally, methoxy functionalized poly(dimethylsiloxane) oligomers that can react into the sol-gel network have been prepared. The intermediates are commercially accessible and the process is scaleable. Utilization of a catalyst-free system eliminates the tendency of the siloxane modifier to undergo undesired rearrangements that are known to occur in the presence of strong acids or bases.

Preparation and Characterization of Amorphous SiO2 Coating SiCp/Cu Composites

2012 ◽  
Vol 512-515 ◽  
pp. 945-950 ◽  
Author(s):  
Xiang Qian Ren ◽  
Bing Bing Fan ◽  
Qian Fei Han ◽  
Peng Hui Wang ◽  
Rui Zhang
Keyword(s):  
Vickers Hardness ◽  
Bending Strength ◽  
Volume Fraction ◽  
Sol Gel ◽  
Eutectic Mixture ◽  
Composite Particles ◽  
Viscous Interaction ◽  
Interfacial Modification ◽  
Sol Gel Process

Hybrid sol–gel process was used to fabricate the precursor particles of amorphous SiO2 coating at the composites of SiCp⁄Cu, and then formed by Vacuum hot-pressed method. Various methods were used to measure the sintered compacts of different SiC volume fraction. The results showed that the densities, bending strength and conductivity were decreased slightly with the increases in the amounts of SiC, and the vickers hardness were increased first and then decreased. The techniques of DTA–TG, SEM–EDS and XRD were used to characterize the phases and the morphologies of the composite particles and composites. It was inferred that the formation of SiO2–Cu2O eutectic mixture in this system and the viscous interaction of amorphous SiO2 improved the interfacial modification of the composites of SiCp⁄Cu.

scholarly journals Organically Modified Silicates by the Sol-Gel Process

1984 ◽  
Vol 32 ◽  
Author(s):  
H. Schmidt
Keyword(s):  
Sol Gel ◽  
New Materials ◽  
Organic Components ◽  
Organically Modified Silicates ◽  
Sol Gel Process ◽  
Inorganic As ◽  
Organically Modified ◽  
General Aspects

ABSTRACTThe introduction of organic groups into inorganic networks by the sol-gel process opens the possibility for the preparation of new materials, and typical properties resulting from inorganic as well as from organic components may be combined. Some general aspects and different examples of material developments are reviewed.

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