The Formation of Molecular Composites by a Modified Solgel Process

1989 ◽  
Vol 155 ◽  
Author(s):  
Ronald B. Lessard ◽  
Mary M. Wallacet ◽  
W. Anthony Oertling ◽  
Chi K. Chang ◽  
Kris A. Berglund ◽  
...  
Keyword(s):  
Sol Gel ◽  
Hydrogen Ion ◽  
Processing Conditions ◽  
Guest Molecules ◽  
Molecular Composites ◽  
Sol Gel Synthesis ◽  
Gel Processing ◽  
Molecular And Electronic Structure ◽  
State Luminescence ◽  
Ceramic Matrices

ABSTRACTStandard sol-gel procedures have been modified to permit sol-gel synthesis to be performed at varying hydrogen ion concentrations and in a variety of organic solvents. These modifications greatly expand the variety of guest molecules that can be incorporated into nondense glassy environments. Processing conditions can be controlled such that the guest compounds generally retain their solution properties thereby allowing new molecular composites to be formed. Reported herein is the incorporation of both porphyrins and metalloporphyrins into silica matrices. Electronic absorption, vibrational, and excited state luminescence properties of the resulting composites clearly demonstrate that the molecular and electronic structure of the porphyrins and metalloporphyrins are preserved during sol-gel processing and in the ceramic matrices. This retention of properties has been shown for guest molecules doped into monoliths as well as films.

Sol-Gel Synthesis, Thermal Behavior of Nanopowders and Chemical Stability of La1 – xHoxPO4 Ceramic Matrices

2018 ◽  
Vol 44 (5) ◽  
pp. 440-449 ◽  
Author(s):  
L. P. Mezentseva ◽  
A. V. Osipov ◽  
V. L. Ugolkov ◽  
A. A. Akatov ◽  
V. A. Doilnitsyn ◽  
...  
Keyword(s):  
Thermal Behavior ◽  
Chemical Stability ◽  
Sol Gel ◽  
Sol Gel Synthesis ◽  
Ceramic Matrices

A Molecular Route to Dip-coated Transition Metal Nitride Thin Films.

2004 ◽  
Vol 848 ◽  
Author(s):  
Andrew W. Jackson ◽  
Andrew L. Hector
Keyword(s):  
Thin Films ◽  
Transition Metal ◽  
Spin Coating ◽  
Sol Gel ◽  
Particle Growth ◽  
Dip Coating ◽  
Stable Emulsion ◽  
Transition Metal Nitride ◽  
Sol Gel Synthesis ◽  
Gel Processing

ABSTRACTThere is an increasing interest in sol-gel synthesis of nitrides. The ability to deposit films of these materials by dip- or spin-coating will increase the range of applications in which they are viable and is an important step toward general sol-gel processing of nitride materials.With transition metals, the ammono based analogue of the well established alkoxy route to gels is inherently difficult to control. Due to the basicity of the system, the overwhelming tendency is of the starting materials to favour particle growth which results in a precipitate rather than a stable emulsion, unless both environment and synthetic pathway are carefully controlled. Hence reports to date of sol-gel routes to nitrides describe production of powders. We report work on a sol-gel route to titanium nitride with the ammonolysis of titanium amides controlled by temperature and chemical moderators, resulting in stable emulsions useful for dip-coating.

Features of silicon– and titanium–polyethylene glycol precursors in sol–gel synthesis of new hydrogels

2015 ◽  
Vol 3 (27) ◽  
pp. 5490-5500 ◽  
Author(s):  
T. G. Khonina ◽  
A. P. Safronov ◽  
M. V. Ivanenko ◽  
E. V. Shadrina ◽  
O. N. Chupakhin
Keyword(s):  
Polyethylene Glycol ◽  
Sol Gel ◽  
Water Soluble ◽  
Sol Gel Synthesis ◽  
Gel Processing

The formation of organic/inorganic hydrogels based on silicon and titanium polyethylene glycolates, new biocompatible water-soluble precursors in sol–gel processing, was investigated.

Chemical Processing and Properties of Nanocrystalline BaTiO3

1992 ◽  
Vol 271 ◽  
Author(s):  
Z. Xu ◽  
H. K. Chae ◽  
M. H. Frey ◽  
D. A. Payne
Keyword(s):  
Grain Size ◽  
Thermal Processing ◽  
Room Temperature ◽  
Sol Gel ◽  
Thin Layers ◽  
Silicon Substrates ◽  
Chemical Processing ◽  
Temperature Structure ◽  
Processing Conditions ◽  
Gel Processing

ABSTRACTBarium titanate (BaTiO3) thin layers were prepared by sol-gel processing. Details are reported for the synthesis route from methoxyethoxide precursors. Partially hydrolyzed solutions were spin-cast onto metallized silicon substrates, and a multilayering technique was used to develop sub-micron structures. Information is reported on the thermal processing conditions used and the development of structure. Crystallization started at 600°C and was fully developed by 700°C. The room temperature structure was cubic, and the grain size was 25–50 nm. Details are reported for the dielectric properties. Ferroelectricity was not observed. Dielectric constant (200–300) increased with increasing grain size, and was stable with respect to temperature, field and frequency. The properties are attractive for potential integrated capacitor applications.

Sol-Gel Processing of Transparent MgAl2O4

1988 ◽  
Vol 121 ◽  
Author(s):  
Yuan-Fu Yu ◽  
Sangvavann Heng ◽  
Tai-Il Mah ◽  
Edward E. Hermes
Keyword(s):  
Sol Gel ◽  
Ceramic Materials ◽  
Metal Alkoxide ◽  
Solvent Ratio ◽  
Processing Conditions ◽  
Chemical Additives ◽  
Control Chemical ◽  
High Degree ◽  
Gel Processing ◽  
Hydrolysis Of

ABSTRACTHigh-purity, transparent monolithic spinel (MgAl2O4) was synthesized via the hydrolytic thermal decomposition of mixed alkoxide organo-metallic precursors. Several factors, such as the metal alkoxide concentration in various solvents, the water to solvent ratio, and the reaction temperatures affect the hydrolysis of the mixed alkoxides. These factors also influence the transparency of the resulting sols and gels. The degree of transparency of the sols and gels is also influenced by such factors as pH and drying control chemical additives. Variations in the processing conditions during drying, aging, and sintering of the gels produced ceramic materials with high degree of transparency.

Preparation of Multicomponent Ceramic Powders by Sol-Gel Processing

1990 ◽  
Vol 180 ◽  
Author(s):  
J.R. Bartlett ◽  
J.L. Woolfrey
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Processing Conditions ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
X Ray ◽  
Acidic Conditions ◽  
Powder Properties ◽  
Gel Processing ◽  
Hydrolysis Of

ABSTRACTSol-gel methods have been applied to the production of the multicomponent ceramic, Synroc B. These techniques involved the hydrolysis of a mixture of Ti and Zr, alkoxides peptising to form a sol and subsequent sorption of Al3+, Ba2+ and Ca2+ cations under acidic conditions. Powder properties were examined by a variety of techniques, including electron microscopy, x-ray diffraction, N2 sorption, and differential thermal analysis. The effects of processing conditions on the physical properties of the powders are discussed.

Pentadionate: An Alternate Sol-Gel Method for the Synthesis of Ferroelectric Ba1−xSrxTiO3

1999 ◽  
Vol 606 ◽  
Author(s):  
Pramod K. Sharma ◽  
K. A. Jose ◽  
V. V. Varadan ◽  
V. K. Varadan
Keyword(s):  
Metal Oxides ◽  
Sol Gel ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Barium Strontium ◽  
Transitional Metal ◽  
Heat Treated ◽  
Transitional Metal Oxides ◽  
Sol Gel Synthesis ◽  
Gel Processing

AbstractSol-gel synthesis of transitional metal oxides is one of the important technique to obtain the pure and homogenous materials at low temperature. In this work, Barium strontium titantate (BST) was synthesized by sol-gel processing using 2,4-pentadionate as the precursors of metal oxides. The Ba1−xSrxTiO3 was prepared for four values of x i.e. 0.2, 0.4, 0.5 and 0.6. The obtained powders were heated from 400 °C to 800 °C at the interval of 100 °C to determine the temperature of crystallization. The phase of the final products was investigated by x-ray diffraction (XRD). Two particle sizes (< 100 nm and 200-400 nm) were observed under the scanning electron microscope (SEM) of the heat treated xerogel. The dielectric properties were determined by impedance analyzer at the frequency of 1MHz and explained in detail for the different values of x.

Sol-Gel Synthesis of GdAlO3 Buffer Layers on SrTiO3 (100) Substrates

2007 ◽  
Vol 124-126 ◽  
pp. 647-650
Author(s):  
Jae Cheol Bang ◽  
Jin Hyeok Kim ◽  
Frederick F. Lange
Keyword(s):  
Single Crystal ◽  
Sol Gel ◽  
Precursor Solution ◽  
Buffer Layers ◽  
Binary Solvent ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Synthesis ◽  
Relationship Of ◽  
Gel Processing

To identify the possibility of using GdAlO3 (GAO) as a buffer layer for YBa2Cu3O7-δ (YBCO) coated superconductor wire, we report the result of GAO deposition on SrTiO3 (STO) single crystal substrates by sol-gel processing. Precursor solution was prepared by dissolving stoichiometric quantities of gadolinium hexahydrate and aluminum isoproxide in a mixed binary solvent (2-4 pentanedione:methyl alcohol=1:1). The solutions were spin-coated on STO (100) single crystal substrates and heated at 500~1100 for 2 h in wet Ar-5% H2 atmosphere. A FESEM observation of the surface morphology of the GAO has shown that it has a very smooth surface with a faceted morphology indicating epitaxy. It was shown in x-ray diffraction characterization that epitaxial GAO films with epitaxial orientation relationship of (001)[112]GAO||(100)[110]STO have been grown on STO (100) substrates.

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