Materials Literature
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The dynamics of the fragile glass-forming orthoterphenyl have been investigated by transient grating experiments with an heterodyne detection technique. We measured the relaxation processes of this glass former over more than six decades in time with an excellent signal-to-noise ratio. Acoustic, structural, and therma…
We report ab initio calculations of quasiparticle lifetimes in graphite, as determined from the imaginary part of the self-energy operator within the GW approximation. The inverse lifetime in the energy range from 0.5 to 3.5 eV above the Fermi level presents significant deviations from the quadratic behavior naively e…
Low-dose−high-resolution electron microscopy (LD−HREM) was used to analyze the structure of regularly twisted poly( m -phenylene isophthalamide) (MPDI) strands formed by slow crystallization from solution. The MPDI chains were found to aggregate into regular assemblies exhibiting uniform twisting at several different…
Abstract In polymer blends, the composition and microcrystalline structure of the blend near surfaces can be markedly different from the bulk properties. In this study, the enzymatic degradation of poly(ε‐caprolactone) (PCL) and its blends with poly(styrene‐ co ‐acrylonitrile) (SAN) was conducted in a phosphate buffer…
Abstract A series of eight polyurethane elastomers was prepared using a two‐step bulk polymerization procedure to investigate the effect of the siloxane chain extender 1,3‐bis(4‐hydroxybutyl)1,1,3,3‐tetramethyldisiloxane (BHTD) on polyurethane properties and morphology. All polyurethanes were based on 40 wt % hard seg…
We use quantum-mechanical modeling to study the effect of local and long-range disorder on the incorporation energy, optical, IR, and XPS spectra of a peroxy linkage defect in amorphous silica $(a\ensuremath{-}{\mathrm{SiO}}_{2}).$ We discuss the methods to simulate amorphous structures and investigate to which extent…
Despite extensive investigation of Bombyx mori silk fibroin structures by many experimental methods, e.g., X-ray diffraction, molecular modeling calculation, and solid static 13 C NMR spectroscopy, a set of fingerprint structural parameters remains unavailable both for the silk I and the silk II forms. In this study,…
Abstract The interfacial reaction of the polyethylene (PE)/starch blend system containing the reactive compatibilizer maleated polyethylene (m‐PE) was directly characterized by Fourier transform infrared (FTIR) spectroscopy. A significant amount of anhydride groups on m‐PE existed as hydrolyzed forms, resulting in a l…
We study theoretically the thermodynamic properties and spin dynamics of a class of magnetic rings closely related to ferric wheels, antiferromagnetic ring systems, in which one of the Fe (III) ions has been replaced by a dopant ion to create an excess spin. Using a coherent-state spin path integral formalism, we deri…
A positive working low-molecular-weight photoresist based on partially t-Boc protected tetra-C-methylcalix[4]resorcinarene (t-Boc C-4-R) and a photoacid generator (PAG), diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS) has been developed. t-Boc C-4-Rs were prepared by the reaction of C-4-R with di-tert-but…
We report Raman and x-ray diffraction studies of polycrystalline ${\mathrm{Ba}}_{x}{\mathrm{Sr}}_{1\ensuremath{-}x}{\mathrm{TiO}}_{3}$ (BST) prepared by the sol-gel technique in the range of $x=0$ to 1.0. Other than a tetragonal to cubic phase transition at composition $x\ensuremath{\approx}0.75$ of the BST powders de…
J. B. Pendry's "Negative Refraction Makes a Perfect Lens" is analyzed. It appears that several statements may be understood in terms of lens design but not in terms of fundamental behavior of light.
Abstract The postpolymerization of vinyl acetate (VAc)‐containing latexes with tert ‐butyl hydroperoxide (TBH)/ascorbic acid (AsA) as a redox initiation system was investigated. Volatile organic compounds (VOCs) such as acetone and tert ‐butyl alcohol were produced in this process. The influence of the TBH/AsA ratio,…
Abstract A series of poly(R‐3‐hydroxybutyrate)/poly(ε‐caprolactone)/1,6‐hexamethylene diisocyanate‐segmented poly(ester‐urethanes), having different compositions and different block lengths, were synthesized by one‐step solution polymerization. The molecular weight of poly(R‐3‐hydroxybutyrate)‐diol, PHB‐diol, hard seg…
Deposition of silane-based self-assembled monolayers onto mesoporous ceramic substrates has been found to be substantially faster from supercritical fluids than from typical condensed phase solutions. In addition, the monolayers so prepared display higher silane population density (6.5 vs 4.6 silanes/nm 2 ), fewer def…
Pharmacokinetic characteristics of intravascular macromolecular magnetic resonance imaging (MRI) contrast agents with polyamidoamine dendrimer cores smaller than generation-7 were previously studied in the literature. To evaluate the effects of greater hepatic uptake on the pharmacokinetics of the larger generation de…
We have isolated and characterized chromium complexes of 5,10,15-tris(pentafluorophenyl)corrole [(tpfc)H(3)] (1) in four oxidation states: [(tpfc(*))CrO][SbCl(6)] (6); [(tpfc)CrO] (2); [(tpfc)CrO][Cp(2)Co] (4); and [(tpfc)Cr(py)(2)] (3). Complex 6 was prepared both by electrochemical and chemical oxidation of 2; its f…
Abstract Lignin, extracted from sugarcane bagasse by the organosolv process, was used as a partial substitute of phenol (40 w/w) in resole phenolic matrices. Short sugarcane fibers were used as reinforcement in these polymeric matrices to obtain fiber‐reinforced composites. Thermoset polymers (phenolic and lignophenol…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTNanopatterns by Free-Standing Monolayer Films of Diblock Copolymer Micelles with in Situ Core−Corona InversionByeong-Hyeok Sohn, Seong-Il Yoo, Byung-Wook Seo, Sang-Hyun Yun, and Sang-Min ParkView Author Information Department of Materials Science and Engineering Polyme…
A new mechanism for regulating the stability of colloidal suspensions has been discovered, known as nanoparticle haloing. 1 Colloidal microspheres suspended under conditions near their isoelectric point were stabilized by the addition of highly charged nanoparticles. Such species segregated to regions near negligibly…