Materials Literature
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X-ray diffraction and FTIR and 13 C NMR spectroscopies have been utilized to observe the inclusion compounds (ICs) formed by poly(ethylene oxide) (PEO) and low molecular weight poly(ethylene glycol) (PEG) oligomer with urea (U). We have confirmed that PEO-U-IC formed from solution has a trigonal crystal structure, whi…
The nature of dielectric relaxation is studied in a number of supercooled monohydroxy alcohols in the frequency range (10 6 −10 -3 Hz) at temperatures above 77 K. Differential scanning calorimeter (DSC) measurements are also carried out on all the alcohols above 100 K. The temperature dependence of the relaxation rate…
Mammalian and yeast cells contain three isozymes of isocitrate dehydrogenase: mitochondrial NAD- and NADP-specific enzymes and a cytosolic NADP-specific enzyme. Independent metabolic functions of these enzymes in Saccharomyces cerevisiae were examined by analyses of expression and of phenotypes displayed by mutants co…
Phase behavior and dynamics of liquid−liquid phase separation in binary blends of crystalline polymers, viz., poly(vinylidene fluoride) (PVF 2 ) and poly(butylene adipate) (PBA), have been studied by means of time-resolved light scattering. According to our previous calorimetric study, a single glass transition and tw…
Abstract Dissolution and crystal growth on the (010) cleavage surface of mineral gypsum have been studied by scanning force microscopy, which allows observation of surfaces while they are in contact with aqueous solutions. Etch pits formed on the (010) surface in contact with solutions undersaturated with respect to g…
Using picosecond transient absorption spectroscopy we have examined the dynamics of Cp*Ir(CO) 2 (Cp* = C 5 Me 5 ) in cyclohexane and Cp*Rh(CO) 2 in n -pentane solution at room temperature following 295-nm UV excitation. A transient absorption with an instrument limited risetime was observed for Ir from 440 to 740 nm a…
We model the static and dynamic wetting properties of nonsoluble liquids on surfaces protected by end-grafted molten polymers. We show that in many situations the spreading dynamics should be controlled by viscoelastic phenomena in the polymer films. Temperature changes can cause the spreading velocities to be varied…
The new heteropolyperoxometalate compounds [NMe4][(Me2AsO2){MoO(O2)2}2]1, [NMe4][(Ph2PO2){MoO(O2)2}2]2, [NBun4][(Ph2PO2){WO(O2)2}2]3 and [NH4][(Ph2PO2){MoO(O2)2(H2O)}]4 have been isolated and their crystal structures determined. Compounds 1–3 are dinuclear, whilst compound 4 is mononuclear; in all four structures the…
We report here a comparison of the ability of the monodentate Lewis base n -propylamine and the bidentate molecule ethylenediamine to quench the photoluminescence of light-emitting silicon in three different structural environments. These include porous silicon fabricated from p-type substrates; porous silicon from n-…
New discotic liquid crystals with one, two, or three reactive acrylate end groups were synthesized. They exhibit a wide discotic nematic phase and show spontaneous homeotropic alignment between substrates. The photoinitiated polymerization of these materials was studied. “In-situ photopolymerization” of these disklike…
Cu II - and Zn II -based donor−acceptor porphyrins have been examined for second-order nonlinear optics using the hyper-Rayleigh scattering technique at 1064 nm. Introduction of the metal ions enhances the first hyperpolarizability (β) of the free-base donor−acceptor porphyrins significantly. The open shell Cu II (d 9…
The properties of diluted symmetric A−B diblock copolymers at the interface between A and B homopolymer phases are studied by means of Monte Carlo (MC) simulations of the bond fluctuation model. We calculate segment density profiles as well as orientational properties of segments, of A and B blocks, and of the whole c…
The time dependence of the diffusion process at the interface between two thin films of protonated and deuterated poly(methyl methacrylate) (PMMA) is studied. By neutron reflection, we investigate both the form and the width of the interface between the two polymer layers with subnanometer resolution. At small diffusi…
One-electron reduction of [Pt(bpy) 2 ] 2+ (bpy = 2,2‘-bipyridyl) in aqueous solution results in the formation of black-green lustrous needles on solid electrodes. The crystalline needles grow perpendicularly from the substrate surface and reach lengths of 1−2 cm. Elemental analysis, X-ray photoelectron spectroscopy, a…
We present an experimental study of the effects of hydrophilic, nonadsorbing polymers on the stability of monodisperse oil-in-water emulsions. Above some threshold polymer concentration, the chains induce droplet segregation into fluid and solid phases due to the depletion effect. At higher polymer concentrations, pol…
The factors which affect the adherence of a bacteria cell to the surface of a biomaterial include the surface chemistry of the cell and material, as well as the composition of the adsorbed protein layer when the biomaterial is exposed to circulating blood. In an effort to better understand the mechanisms by which bact…
The motion of a melt-blown fiber was experimentally measured. After exiting the spinning die, a melt-blown fiber was found to vibrate with frequencies and amplitudes that were functions of the operating conditions (polymer flow rate, polymer temperature, air flow rate, and air temperature). Fiber amplitude was measure…
A photochromic saccharide receptor with a diarylethene photoswitch changes the binding event with glucose by photoirradiation.
Racemic poly(3-hydroxybutyric acid) (P(3HB)) was prepared by the ring-opening polymerization of racemic β-butyrolactone (β-BL) in the presence of methylaluminoxane and fractionated into five components with various isotactic diad fractions ([ i ]) varying from 0.88 to 0.54. The degree of X-ray crystallinity of isotact…
Phosphonates are water treatment chemicals that are effectively utilized in many industrial processes as dispersants, bleaching agents, or scale and corrosion inhibitors. In many of these applications, the phosphonates are able to react with divalent cations such as calcium to form stable divalent cation−phosphonate p…