Materials Literature
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The derivation of effective equations for pressure wave propagation in a bubbly fluid at very low void fractions is examined. A Vlasov-type equation is derived for the probability distribution of the bubbles in phase space instead of computing effective equations in terms of averaged quantities. This provides a more g…
Microphase separation was induced from homogeneous polystyrene- block -polyisoprene (SI diblock) copolymer by grafting of a liquid-crystalline (LC) monomer onto the polyisoprene (PI) block. The origin of the formation of microdomain structure in the side-chain LC block copolymer from a homogeneous SI diblock copolymer…
The atomic charges derived from the extended electronegativity function, which includes the influence of bonding, were examined. These atomic charges were found to conform to an intuitive notion of atomic charge at the intermolecular, interatomic, and electronic levels. In addition, a new model for the core ionization…
We report differences in the thermodynamic behavior of compositionally symmetric ABC and BAC triblock copolymers near the order−disorder transition temperature and of binary ABC/BAC copolymer blends: poly(styrene- b -isoprene- b -dimethylsiloxane) (SID) and ISD with segment volume fractions near 0.33 and similar molec…
Polyethylene and isotactic polypropylene having 1,2- or 1,3-disubstituted cyclopentane structures were prepared by copolymerization of ethylene or propylene with cyclopentene (CPE) or 1,5-hexadiene (HD) using zirconocene catalysts. Effect of the cyclopentane structures on the melting point and crystalline structure of…
A new positive working photosensitive alicyclic polyimide precursor based on poly(amic acid tert -butyldimethylsilylester) ( 3 ) and 2,3,4-tris[2-diazo-1-(2 H )-naphthalenone-4-sulfonyloxy]benzophenone ( D4SB ) as a photosensitive compound has been developed. Polymer 3 was prepared by ring-opening polyaddition of bicy…
The crystallization behavior of functionalized polymethylene chains with carbamate esters placed periodically between alternating docosyl and octyl segments has been examined with infrared spectroscopy. Specific features of both the interactions and the chain conformation have been found. The crystallization kinetics,…
The alignment kinetics of the orientation/reorientation behavior of the microphase of a lamellarPS- b -PI diblock copolymer under large-amplitude oscillatory shear conditions is studied. By online monitoring the degree of the mechanical nonlinearity during the orientation process as determined via the higher harmonics…
Admicellar polymerizations were conducted in aqueous solutions to form electrically conducting poly(pyrrole) (PPy) ultrathin films on mica and graphite. Separate solutions were used for monomer adsolubilization and polymerization, so that at the start of the reaction step, the only monomer in solution was localized at…
Increasing the net fixed-charge density in multilayer polyelectrolyte membranes using postdeposition reactions results in large enhancements of ion-transport selectivity. To control the fixed-charge density in poly(acrylic acid)/poly(allylamine hydrochloride) (PAA/PAH) films, we partially derivatized PAA using 2-nitro…
Calorimetric and X-ray diffraction investigations of anhydrous α trehalose obtained by dehydration of its dihydrate form have been performed. The results show that the structural and thermodynamic properties of the dehydrated state strongly depend on the kinetics of water loss. A fast dehydration promotes the formatio…
The formation of CuS nanoparticles from Cu(NO 3 ) 2 and Na 2 S by the mixing of two separate water-in-carbon dioxide (W/C) microemulsions supported by the sodium salt of bis(2,2,3,3,4,4,5,5-octafluoro-1-pentyl)-2-sulfosuccinate (di-HCF4) was investigated. At a water-to-surfactant ratio of 10 and a copper concentration…
Straight acrylic composite nanoparticles with a mean diameter of 132 nm and a mushroomlike particle morphology consisting of a soft poly( n -butyl acrylate) phase with a caplike poly(methyl methacrylate) hard phase covering one side of the particle were prepared by emulsion polymerization. The particles show oriented…
The effect of entanglements on deformation properties of end-linked networks was investigated using Monte Carlo simulations. Model tetrafunctional networks were prepared by cross-linking precursor monodisperse chains in the framework of the bond fluctuation model (BFM). The degree of entanglement in these networks was…
Carbon nanoprobes were utilized in tapping mode atomic force microscopy investigations to highlight the topographic differences between poly(amidoamine) (PAMAM) dendrimers, two-dimensional arrays of PAMAM dendrimers, and PAMAM core−shell tecto(dendrimers). The PAMAM core−shell tecto(dendrimers) used for this study con…
Alternating deposition of oppositely charged polyelectrolytes on porous supports is an attractive way to synthesize selective, ultrathin ion-separation membranes. This study reports the use of Cu 2+ as a template in poly(acrylic acid) (PAA)/poly(allylamine hydrochloride) (PAH) membranes to control fixed charge density…
We present results of first-principles density functional calculations for the candidate multiferroic magnetoelectric, bismuth chromite. Although little is known experimentally about BiCrO 3, its chemical neighbors BiMnO 3 and BiFeO 3 are known to be ferromagnetic and ferroelectric respectively, with structural distor…
The phase behavior of a melt of monodisperse rod−coil diblocks is studied. We derive a Landau free energy functional for both a compositional and a nematic order parameter. The excluded volume interaction between the rod blocks is modeled by an attractive Maier−Saupe interaction. The incompatibility between rod and co…
In this report, a novel method for the synthesis of gold nanoparticles on an amorphous silica support is described wherein silanol groups on the surface of the fumed silica spontaneously reduce aqueous chloroaurate ions. This results in the formation of gold nanoparticles that are bound fairly strongly to the fumed si…
Surface modifying macromolecules (SMM) were synthesized and blended into the casting solution of poly(ether sulfone). The solution was cast to films with thickness of 0.12 and 0.24 mm. The cast films were placed in an oven with forced air circulation for periods of 3, 5, 7, and 2000 min to remove the solvent, before b…