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Gel Materials (gel + material)
Selected AbstractsA New Sol,Gel Material Doped with an Erbium Complex and Its Potential Optical-Amplification Application,ADVANCED FUNCTIONAL MATERIALS, Issue 6 2005L.-N. Sun Abstract The crystal structure of a ternary Er(DBM)3phen complex (DBM,=,dibenzoylmethane; phen,=,1,10-phenanthroline) and its in-situ synthesis via a sol,gel process are reported. The infrared (IR), diffuse reflectance (DR), and fluorescence spectra of the pure complex and the Er3+/DBM/phen co-doped luminescent hybrid gel, formed via an in-situ method (ErDP gel), have been investigated. The results reveal that the erbium complex is successfully synthesized in situ in the ErDP gel. Excitation at the maximum absorption wavelength of the ligands resulted in the typical near-IR luminescence (centered at around 1.54,,m) resulting from the 4I13/2,,,4I15/2 transition of the Er3+ ion, which contributes to the efficient energy transfer from the ligands to the Er3+ ion in both the Er(DBM)3phen complex and the ErDP gel (an antenna effect). The full width at half maximum (FWHM) centered at 1541,nm in the emission spectrum of the ErDP gel is 72,nm, which has potential for optical-amplification applications. Further theoretical analysis on the Er3+ ion in the ErDP gel shows that it appears to be a promising candidate for tunable lasers and planar optical amplifiers. [source] Patterned transparent zinc oxide films produced by sol,gel embossingPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2008J. Rao Abstract A low cost zinc oxide embossing technique is reported as a method of fabricating structures relevant to a variety of applications. A zinc based sol,gel material was prepared from zinc acetate [Zn(C2H3O2)2], monoethanolamine [H2NC2H4OH] and isopropanol. The sol,gel was cast into a polydimethylsiloxane (PDMS) mould a track design, placed in contact with the substrate and dried under vacuum at 70 °C for 3 hours. The formed track pattern was further densified to provide a stable conductor film that retained the embossed shape. An optimum Zn sol,gel content of 0.6 M was identified. The embossed films had a transparency of greater than 83% in the visible region. The optical bandgap energy was evaluated to be 3.306 eV. The influence of ZnO sol,gel film synthesis and embossing parameters on the microstructure, morphology and optical transparency of fabricated structures is described. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Preparation and characterization of complex gel of type I collagen and aluminosilicate containing imogolite nanofibersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2010Asuka Nakano Abstract Complex gel materials of Type I collagen and aluminosilicate containing imogolite nanofibers were prepared as opaque gel by mixing an acidic fine dispersion of aluminosilicate with an acidic solution of collagen. The product was stained blue by Coomassie Brilliant Blue (CBB), indicating that the gel contained collagen. A white sponge was obtained after lyophilization of the complex gel. Elemental analysis revealed that the complex contains C, H, N, Al, and Si atoms; and the compositional ratio of aluminosilicate/collagen (w/w) was calculated as 0.75 for the complex gel when aluminosilicate was mixed with an equal quantity of collagen. Transmission electron microscope (TEM) observation showed that aluminosilicate nanofibers were homogeneously distributed in the collagen matrix. The thermogravimetric analysis (TGA) curve of the complex was not a simple summation of each components, and especially, the weight loss step corresponding to detachment of the adsorbed water observed in aluminosilicate became difficult to distinguish, suggesting that the adsorbed water was removed in the complexation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Real-time Fourier transform infrared study of the free-radical ultraviolet-induced polymerization of a hybrid sol,gel.JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2003Abstract Free-radical photocurable hybrid sol,gel materials have gained special interest during the last decades. Compared to thermally processed materials, they present the advantages of fast curing, low energy consumption, and spatiotemporal control of the reaction. Although comprehension of the photochemical step is fundamental, little is known about the characteristic of photochemistry in this kind of material. Real-time Fourier transform infrared spectroscopy was used to study the photopolymerization of a hybrid sol,gel upon ultraviolet irradiation. Various photoinitiator systems were tested for their efficiency in inducing the polymerization of pendant polymerizable moieties anchored on a partially condensed silicate network. The presence of O2 and the nature of the polymerizable function were shown to be crucial factors in the photoinduced process. The effects of the photoinitiator concentration and light intensity were also studied. These results were explained in terms of classical kinetic models developed for all-organic photopolymers to point out the distinctive aspects related to the use of photoinitiated polymerization in hybrid sol,gel materials. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 831,840, 2003 [source] Real-time Fourier transform infrared study of free-radical UV-induced polymerization of hybrid sol,gel.JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2003Abstract Free-radical photocurable hybrid sol,gel materials have gained special interest. They are becoming more and more widely used for applications in coatings, optics, sensors, catalysis, and so forth. The photochemical step is a fundamental step in the elaboration of this kind of hybrid sol,gel. However, little is known about the specifics of the photochemistry in this material. The relation between the organic and the inorganic part is investigated. Hydrolysis and condensation reactions were characterized by 29Si NMR. A precise description of the material before irradiation is of paramount importance to understand photoinduced phenomena. Real-time Fourier transform infrared spectroscopy was used to examine the photopolymerization of hybrid sol,gel under UV irradiation. UV photopolymerization occurred efficiently in hybrid sol,gel although inhibition of free-radical polymerization by molecular oxygen was pronounced. Important structural modifications during irradiation were also measured. They concern both inorganic and organic parts of the hybrid material. The condensation state of the silicate network was of crucial importance. The presence of the silicate backbone did not limit the final conversion ratio. On the contrary, photopolymerization occurred more efficiently for systems with a higher degree of condensation. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 716,724, 2003 [source] Polyelectrolyte-in-Ionic-Liquid ElectrolytesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 17 2003Churat Tiyapiboonchaiya Abstract Novel polymer electrolyte materials based on a polyelectrolyte-in-ionic-liquid principle are described. A combination of a lithium 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSLi) and N,N,-dimethylacrylamide (DMMA) are miscible with the ionic liquid, 1-ethyl-3-methylimidazolium dicyanamide (EMIDCA). EMIDCA has remarkably high conductivity (,,2,·,10,2 S,·,cm,1) at room temperature and acts as a good solvating medium for the polyelectrolyte. At compositions of AMPSLi less than or equal to 75 mol-% in the copolymer (P(AMPSLi- co -DMAA)), the polyelectrolytes in EMIDCA are homogeneous, flexible elastomeric gel materials at 10,,,15 wt.-% of total polyelectrolyte. Conductivities higher than 8,·,10,3 S,·,cm,1 at 30,°C have been achieved. The effects of the monomer composition, polyelectrolyte concentration, temperature and lithium concentration on the ionic conductivity have been studied using thermal and conductivity analysis, and pulsed field gradient nuclear magnetic resonance techniques. Comparison of the measured and calculated lithium conductivity at 30,°C. [source] Chromogenic polymer gels for reversible transparency and color control with temperature at a constant volumePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7 2002A. Seeboth Abstract The preparation and characterization of novel chromogenic materials has developed extremely rapid in the last years. Among them, thermotropic and thermochromic polymer gel networks have met with growing interest, because of their advanced properties. These novel polymer gels exhibit pronounced changes in transparency and/or color intensity in a practically relevant temperature range. For many future technical applications it is an essential condition, that the volume of the used gel materials is independent of temperature. A current overview of this field is given. Copyright © 2002 John Wiley & Sons, Ltd. [source] | ||||||||||