Materials Literature
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Abstract Based on the static and dynamic mechanical properties of the corresponding blends, the compatibility of six thermoplastic elastomers with polyvinyl chloride (PVC) was investigated. A terpolymer of ethylene, vinyl acetate and carbon monoxide (EVACO) was shown to give the optimal properties for the processing o…
It has been suggested by several authors that SrTiO3 layers in SrTiO3 –BaTiO3 superlattices should be tetragonal and ferroelectric at ambient temperatures, like the BaTiO3 layers, rather than cubic, as in bulk SrTiO3, and that free-energy minimization requires continuity of the polarization direction. A recent ab init…
A canopy-shaped pyrrole derivative 2 was prepared, in which a sterically demanding pendant group is juxtaposed to the pyrrole fragment to minimize interstrand pi-pi stacking interactions in the resulting polymer. Anodic polymerization of 2 afforded highly conductive poly(2), the electronic structure of which was probe…
Lead zinc niobate–lead titanate (PZN–PT) single crystals show very large piezoelectric strains for electric fields applied along the unit cell edges e.g. [001] R . It has been widely reported that this effect is caused by an electric field induced phase transition from rhombohedral ( R 3 m ) to monoclinic ( Cm or Pm )…
Both positive and negative replicas of copolymer arrays are produced using crosslinked poly(dimethylsiloxane). Negative replicas of the nanoscopic features are manufactued by entrapping air within the microdomains. Positive replicas are produced with ∼ 1:1 aspect ratios by the PDMS filling the nanoscopic, cylincrical…
Abstract The promise of nanotechnology is increasingly being realized as governments, universities, public and private research laboratories, and the various industrial sectors devote resources to this emerging area. Estimates for the economic impact of nanotechnology on existing global markets exceed 700 billion by t…
Abstract The synthesis, characterization, and ring‐opening polymerization of a new cyclic carbonate monomer containing an allyl ester moiety, 5‐methyl‐5‐allyloxycarbonyl‐1,3‐dioxan‐2‐one (MAC), was performed for the first time. MAC was synthesized in five steps in good yield beginning from the starting material, 2,2‐b…
5‐Cyano‐2‐(3,4,5‐trialkoxybenzoylamino)tropones form hexagonal structures in both liquid‐crystalline and gel states. The Figure shows an environmental scanning electron microscopy image of octanol gels. Hydrogen bonding between the tropone carbonyl group and the NH group of troponoid amides plays an important role in…
Abstract X‐ray diffraction peak profile analysis (DPPA) is a powerful tool for the characterisation of microstructures either in the bulk or in loose powder materials. The evaluation and modelling procedures have been developed together with the experimental techniques. The dislocation density and structure, as obtain…
Abstract In this brief communication, we would like to review present data on fatigue performance of ultra‐fine grain materials fabricated by severe plastic deformation (SPD) and to discuss the possible mechanisms of their plastic deformation and degradation in light of currently available experimental data. The most…
Abstract We discuss the role coarse‐grained models play in investigating collective phenomena in bilayer membranes and place them in the context of alternative approaches. By reducing the degrees of freedom and applying simple effective potentials, coarse‐grained models can address the large time scales and length sca…
It is well-known that the azido bridge gives rise antiferromagnetic (AF) or ferromagnetic (F) coupling depending on its coordination mode, namely end-to-end or end-on, respectively. The aim of the present work is to analyse the factors contributing to this different magnetic behaviour. The difference dedicated configu…
Using density functional calculations the phonon dispersion relations, phonon density of states, and free energy of \ensuremath{\theta} and \ensuremath{\alpha} phases of alumina are investigated. The temperature dependence of the free energy indicates that entropy contributes to the destabilization of the \ensuremath{…
A multistep procedure for creating nanohole‐patterned gold films (see Figure) is presented. The steps include the self‐assembly of metal‐loaded polystyrene‐ block ‐poly(2‐vinylpyridine) micelles on GaAs substrates, hydrogen gas plasma treatment, directional reactive ion etching, and gold sputtering. The size and separ…
The effect of introduction of perfluoro alkyl groups into phthalocyanines, as evidenced by the spectroscopic properties of 1,4,8,11,15,18,22,25-octa-fluoro-2,3,9,10,16,17,23,24-octa-perfluoro isopropyl zinc phthalocyanine, ZnF(64)Pc(-2) and its ring-reduced radical anion species, [ZnF(64)Pc(-3)](-), are reported. A co…
[reaction: see text] 6-Bromo-4-(1,2-dihydroxyethyl)-7-hydroxycoumarin (Bhc-diol) can be used under simulated physiological conditions as a photoremovable protecting group for aldehydes and ketones. The single- and two-photon-induced release of benzaldehyde, piperonal, acetophenone, and cyclohexanone is demonstrated.
Abstract A polyhedral oligomeric silsesquioxane (POSS), consisting mainly of a mixture of octahedra, nonahedra, and decahedra with bulky and flexible organic substituents, with three secondary hydroxyls per organic group, was used to modify epoxy networks produced by the homopolymerization of diglycidyl ether of bisph…
Abstract Severe plastic deformation (SPD) can lead to emergence of microstructural features and properties in materials which are fundamentally different from the ones well known for conventional cold deformation. In particular, the instances of unusual phase transformations resulting in development of highly metastab…
Abstract Diffusion is a key property determining the suitability of nanocrystalline materials for use in numerous applications, and it is crucial to the assessment of the extent to which the interfaces in nanocrystalline samples differ from conventional grain boundaries. The present article offers an overview of diffu…
It is shown that the exchange properties of the imino and hydroxyl protons of polyuridilic acid (poly(rU)) allow use of this compound as a chemical-exchange saturation transfer (CEST) contrast agent. A proton/proton sensitivity enhancement factor of over 5000 per imino proton allowed the detection of a few micromolar…