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991.
Thickness dependence of thermally induced changes in surface and bulk properties of Nafion® nanofilms
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Devproshad K. Paul Hyun Ki Shim Javier B. Giorgi Kunal Karan 《Journal of Polymer Science.Polymer Physics》2016,54(13):1267-1277
Thermally induced changes in surface wettability, dewetting behavior, and proton transport of “self‐assembled” nanothin Nafion® films (4–300 nm) on SiO2 substrate is reported. Thermal annealing induces switching of the surface wettability of 55 nm and thinner films from hydrophilic to super‐hydrophobic. Thickness dependence of this behavior is observed with higher annealing temperature required for lower thickness films, indicating highly restrictive mobility of Nafion® ionomer as film thickness decreases. Dewetting is only observed for 4‐nm thin film. Significant suppression in proton conductivity upon thermal annealing was noted. Similarly, two other bulk properties, water uptake and swelling, were found to decrease upon annealing. This work reports a systematic examination of the thickness dependence of thermally induced changes in both surface and bulk properties of ultra‐thin Nafion®. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1267–1277 相似文献
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Castillo-Rodriguez Judith Pereyra Carlos Javier Valente Paulo Seré Andrés Marotti Ricardo E. Hevia Samuel A. Dalchiele Enrique A. del Rio Quero Rodrigo 《Journal of Solid State Electrochemistry》2020,24(4):797-808
Journal of Solid State Electrochemistry - Transparent conductive oxide electrodes and specifically SnO2:F/glass are widely employed substrates in the preparation of optoelectronic devices. This... 相似文献
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Jose M. Guisan Gloria Fernandez-Lorente Javier Rocha-Martin Daniel Moreno-Gamero 《Current Opinion in Green and Sustainable Chemistry》2022
Different strategies for the preparation of efficient and robust immobilized biocatalysts are here reviewed. Different physico-chemical approaches are discussed.i.- The stabilization of enzyme by any kind of immobilization on pre-existing porous supports.ii.- The stabilization of enzymes by multipoint covalent attachment on support surfaces.iii.- Additional stabilization of immobilized-stabilized enzyme by physical or chemical modification with polymers.These three strategies can be easily developed when enzymes are immobilized in pre-existing porous supports. In addition to that, these immobilized-stabilized derivatives are optimal to develop enzyme reaction engineering and reactor engineering. Stabilizations ranging between 1000 and 100,000 folds regarding diluted soluble enzymes are here reported. 相似文献
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Mirela Rada José María Castellano Javier S. Perona Ángeles Guinda 《Biomedical chromatography : BMC》2015,29(11):1687-1692
Analytical interest of OA determination in human serum has increased owing to the increasing interest in pharmaceutical research by pharmaceutical properties. A simple, specific, precise and accurate GC method with flame ionization detector (FID) developed and validated for the determination of oleanolic acid (OA) in human serum (HS). To an aliquot of HS, internal standard was added and a combination of liquid–liquid extraction with a mixture of diethyl ether‐isopropyl alcohol, filtration and consecutive GC resulted in separation and quantification of OA. The organic phase was analyzed using a GC system equipped with a 30 × 0.25 mm i.d. Rtx‐65TG capillary column and FID detection. Total chromatographic time was 10 min and no interfering peaks from endogenous components in blank serum were observed. The OA/internal standard peak area ratio was linearly fitted to the OA concentration (r = 0.992) over the range 10–1500 ng/mL. The mean serum extraction recovery of OA was 96.7 ± 1.0% and the lower limit of quantification based on 5 mL of serum was 10.7 ng/mL. The intra‐day coefficient of variation ranged from 1.3 to 3.6% and inter‐day varied from 1.4 to 4.5%. The developed method was used to study the pharmacokinetics of OA after oral administration in humans. The assay was simple, sensitive, precise and accurate for the use in the study of the mechanisms of absorption and distribution of OA in humans. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Marcos Martínez Francisco Lara Ochoa Raymundo Cruz-Almanza Rubén A. Toscano 《Journal of chemical crystallography》1996,26(7):451-456
The title compound crystallizes in a solvent-free form and also includes solvent molecules. The X-ray structure analysis reveals that in the both crystal forms the cyclododecatetraene ring in the host molecules adopts a sofa conformation. The guest molecules occupy the channels formed among columns of stacked host molecules.Contribution No. 1452 of Instituto de Química, UNAM. 相似文献
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Steven R. Woodcock Stacy G. Wendell Francisco J. Schopfer Bruce A. Freeman 《Tetrahedron letters》2018,59(39):3524-3527
15-oxo-Lipoxin A4 (15-oxo-LXA4) has been identified as a natural metabolite of the fatty acid signaling mediator Lipoxin A4. Herein, we report a total synthesis of the methyl ester of 15-oxo-LXA4 to be used in investigations of potential electrophilic bioactivity of this metabolite. The methyl ester of 15-oxo-LXA4 was synthesized in a convergent 15 step (9 steps longest linear) sequence starting from 1-octyn-3-ol and 2-deoxy-d-ribose with Sonogashira and Suzuki cross-couplings of a MIDA boronate as key steps. 相似文献