Materials Literature
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A quantitative model of the rheology of fractionated short chain branched hyperbranched polyesters was developed. The two parameter Schulz-Zzimm were used where the parameters characterized the gamma function. The excellent fits to both the parent HBP and fractions implies that short chain branched HBPs are unentangle…
In this paper we discuss the glass transition and fragility of supercooled confined water. We have used vermiculite clay, a molecular sieve and purple membrane as host materials in order to obtain confinements that are severe enough to avoid crystallization of the water, even in the (for bulk water) experimentally ina…
The phase behaviour of water confined in porous Vycor glass is investigated by means of dielectric measurements. The effective static permittivity ε eff (0) of the sample, which consists of Vycor glass and water confined in the pores, is obtained over a wide range of temperature and pressure. The boiling point of the…
An amphiphilic surfactant, dodecylbenzenesulfonic acid (DBSA), was complexed with poly(ethylene oxide) (PEO) block in poly(1,4-butadiene)- block -PEO (PB- b -PEO) through hydrogen bonding to yield a molecular architecture resembling comb−coil diblock copolymer. For the two binding fractions ( x = 0.5 and 1.0 with x be…
The extent and locus of solubilization of guest and self-assembling surfactant host molecules in aqueous solutions are influenced by a variety of hydrophobic and hydrophilic interactions, as well as by more specific interactions between the various species present. By using a combination of two-dimensional heteronucle…
The structure and magnetocaloric effect (MCE) of rapidly quenched LaFe 11.4 Si 1.6 compound were investigated by means of x-ray diffraction analyses and magnetic measurements. The rapid quenching greatly facilitates the formation of the cubic La(Fe,Si) 13 (1:13 structure) in LaFe 11.4 Si 1.6 alloy. Rietveld analyses i…
The effect of salt concentration on the nanostructure of a spread monolayer of ionic amphiphilic diblock copolymer, (diethylsilacyclobutane)m-b-(methacrylic acid)n, at the air-water interface was directly investigated by in situ X-ray reflectivity and neutron reflectivity techniques. Previously, we had found that a po…
Se han preparado materiales hbridos por medio de reacciones de hidrlisis y condensacin de alcxidos de Si y Ti (TEOS y TBT, respectivamente) y de reacciones de copolimerizacin de stos con polidimetilsiloxano (PDMS). Se han estudiado las citadas reacciones mediante espectroscopia FT-IR, desde el mismo comienzo hasta la…
The thermal decomposition of methanol has been studied on TiO 2 (110) as well as on Cu and oxygen-covered Cu nanoclusters supported on TiO 2 (110) using temperature programmed desorption (TPD). The sizes of the Cu clusters were characterized by scanning tunneling microscopy (STM). Methanol chemistry on the vacuum-anne…
We address the question of the dependence of the fragility of glass forming supercooled liquids on the 'softness' of an interacting potential by performing numerical simulation of a binary mixture of soft spheres with different power n of the interparticle repulsive potential. We show that the temperature dependence o…
Sintering of supported nanocatalysts often leads to the loss of the catalytic activity and selectivity. This paper reports on synchrotron X-ray studies of the thermal stability of supported platinum nanoparticles produced by cluster deposition on the naturally oxidized surface of a silicon wafer (SiO 2 /Si(111)). The…
Abstract Biodegradable hollow nanocapsules were successfully prepared by a combination of layer-by-layer assembly and the silica template method. Ultrathin polymer films were constructed on the surface of the silica nanoparticles by layer-by-layer assembly of oppositely charged biodegradable polyelectrolytes, chitosan…
Treatment of a diblock copolymer containing an alkyne-functional block (polystyrene- block -poly(4-(phenylethynyl)styrene)) with dicobalt octacarbonyl (Co 2 (CO) 8 ) leads to selective incorporation of Co 2 (CO) 6 groups in the alkyne block. Examination of these composites in bulk and thin films by transmission electr…
Abstract Photochemical and enzymatic methanol synthesis from HCO3− with formate dehydrogenase (FDH), aldehyde dehydrogenase (AldDH), and alcohol dehydrogenase (ADH) via the photoreduction of MV2+ using ZnTPPS photosensitization was developed and the amount of produced methanol was 0.55 μmol dm−3 after 4-h irradiation.
The sequences and three-dimensional structures of the galactokinase, homoserine kinase, mevalonate kinase, and phosphomevalonate kinase (GHMP) family were compared to identify highly conserved surface residues. The functions of these solvent-accessible residues were assessed by determining the effects of their substit…
The psychrophilic alcohol dehydrogenase (psADH) cloned from Antarctic Moraxella sp. TAE123 exhibits distinctive catalytic parameters in relation to the homologous thermophilic alcohol dehydrogenase (htADH) from Bacillus stearothermophilus LLD-R. Amide hydrogen-deuterium (H/D) exchange studies using Fourier-transformed…
Experimental techniques for studying the behaviour of water in confined geometry using neutron scattering and NMR methods are reviewed. A brief survey is given of earlier work on sol–gel silicas and these findings are updated by reference to current work on MCM- and SBA-type silicas. Particular attention is focused on…
In contrast to non-associating liquids such as oils or organic solvents, whose viscosity diverges when they are confined by solid surfaces to films thinner than about ten molecular diameters, recent studies reveal that salt-free water remains fluid, with a viscosity close to its bulk value, even when confined to films…
Characterization of palladium catalysts, supported on alumina and alumina modified by zirconia added by impregnation, was performed by CO adsorption from 143 to 298 K and monitored by infrared spectroscopy. It was found that the population of the Al3+ octahedral sites in the alumina decreased by the addition of zircon…
We review our incoherent quasielastic neutron scattering (QENS) studies of the dynamics of supercooled water confined in nanoporous silica materials. QENS data were analysed by using the relaxing cage model (RCM) previously developed by us. We first use molecular dynamics (MD) simulation of the extended simple point c…