Materials Literature
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2H-NMR spin-lattice relaxation times T1 of phenyl ring deuterated toluene have been measured as a function of temperature (75–290 K) at Larmor frequencies between 13.8 and 55.8 MHz. The results are interpreted by assuming a Cole–Davidson rotational correlation time distribution for the α process dominating T1 at tempe…
The effect of substrate surface hydrophobicity on fibronectin (Fn) adsorption and endothelial cell adhesion strength was studied. Bovine aortic endothelial cells (BAEC) were plated for 2 h with and without preadsorbed Fn on slides coated with homopolymers and copolymers of hydrophilic polyhydroxyethylmethacrylate (pol…
The Fe III /Fe II and Fe II /Fe I reduction potentials of a series of model hemes have been measured by cyclic voltammetry in dimethylformamide at 25 °C as a function of the concentration of added axial ligands. The six porphyrinate ligands utilized were tetraphenylporphyrin (TPP), tetramesitylporphyrin (TMP), and a s…
Atomic force microscopy (AFM) makes it possible to directly detect morphological changes on the surface of a zeolite that are due to dissolution when the crystal is immersed in either an alkaline (0.1 N NaOH) or acidic (0.2 N H 2 SO 4 ) aqueous solution at room temperature. The AFM images revealed for the first time t…
In octadentate complexes of europium(III) based on 1,4,7,10-tetraazacyclododecane, deuteriation studies and measurements of excited state lifetimes in solution reveal that amide N–H and methylene C–H oscillators afford an intramolecular vibronic deactivation pathway of the excited Eu 5D0 emissive state which, coupled…
Mn(II) has been used as a probe to investigate the interacting abilities of the various ligand sites at the surface of starburst dendrimers (SBDs) at different protonation conditions, and as a function of generation ( G ), both for half- and full-generation SBDs ( n .5-SBDs and n -SBDs, respectively). The computer-aid…
A series of copolymers with two structural units 1-(4-nitrophenyl)-2-(4-{[2-(methacryloyloxy)ethyl]ethylamino}phenyl)diazene (DR1M), which contains donor−acceptor substituents in the azobenzene group, and 4-[2-(methacryloyloxy)ethyl]azobenzene (MEA), which has no donor−acceptor substituents was prepared. The maximum o…
Polyurethanes as aqueous dispersions were synthesized and some mechanical properties of the casted films were analysed. Anionomers prepolymers were prepared in bulk by the reaction of poly(propylene oxide), 4,4′-dicyclohexylmethane diisocyanate and dimethylolpropionic acid. The acid group's neutralization was carried…
The dynamical criterion for freezing of three-dimensional colloidal fluids recently proposed by L\"owen, Palberg, and Simon [Phys. Rev. Lett. 70, 1557 (1993)] states that the ratio of the long-time to short-time self-diffusion coefficients has the universal value 0.1 along the fluid freezing line. Based on Brownian dy…
Self consistent mean field (SCF) theory is used to investigate the structure of and interactions between layers of polymer chains tethered to a spherical interface. Traditional methods have combined flat geometry results with the Derjaguin approximation to calculate the interaction potentials between curved surfaces,…
Molecular recognition of glutarimide using 2,6-diamidopyridine units incorporated into dendritic building blocks is examined.
The oxidation of meso-tetrahydrotetraalkylporphyrinogen, which is the chemical and biochemical precursor of porphyrins, has been reexamined using meso-octaalkyl-porphyrinogen as a model compound. This investigation has led to the discovery of oxidized forms of porphyrinogen other than porphyrins, which we call artific…
The influences of oxygen plasma treatment of polyimide (PI) films on the adhesion of electroless copper coatings as well as on the chemical composition of the film surface and the PI surface morphology were investigated. The plasma operating parameters were 1800 W forward power with O2 flowing at a rate of 300 cm3/min…
The characteristic thermal parameters of a platinum-film microbolometer are extracted from the data of two measuring methods. A simple and accurate equivalent circuit model, along with its thermal behavior, is proposed for the device. Applying the model to simulate some device circuits results in good agreement with t…
We present a scaling theory to describe equilibrium conformations of weakly charged polyelectrolyte molecules grafted at one end onto impermeable surfaces of various morphologies (spheres, cylinders) and of arbitrary curvature. We focus on the case of sufficiently densely grafted chains, i.e., on curved polyelectrolyt…
A simple theoretical model describing the effects of pH and salt concentration on the permeability and counterion transport number of variable permeability membranes has been presented and validated experimentally for the case of poly(vinylidene fluoride) membranes graft modified with poly(acrylic acid) chains by radi…
The effect of adding ethylene-propylene copolymer (EPR) into polypropylene (PP), with particular emphasis on the impact fracture characteristics, will be presented in this work. The impact fracture characterization techniques used include the notched Izod impact strength, drop-weight dart impact, and the impact fractu…
Are non‐stick surfaces “the chemical analogue of the perpetual motion machine”, i.e., unattainable? Cheap and simple‐to‐produce systems with ultra‐low surface energy—and so on the way towards this ideal—are polyelectrolyte–surfactant complexes. Polarization micrographs of such systems involving fluorinated surfactants…
This paper sets down in detail the observation, first announced as a note (Romo-Uribe, A.; Windle, A. H. Macromolecules 1993, 26, 7100), of a strident and reversible orientation transition in a specially synthesized series of thermotropic random copolyester melts of the Vectra A900 type. The transition is between the…
The electrohydrodynamic pattern forming instability (EHC) driven by an ac voltage applied to a homeotropically aligned nematic liquid crystal layer is experimentally studied near onset. By controlling an external magnetic field, many different scenarios become accessible. For finite fields various regular convective s…