Materials Literature
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Multilayer films comprising solely negatively charged polyelectrolytes were sequentially assembled based on DNA hybridization. Films prepared from alternating layers of two-block homopolymeric nucleotides (polyA(20)G(20)/polyT(20)C(20)) grew linearly with increasing layer number, as verified by quartz crystal microgra…
The kinetics of poly(ethylene terephthalate) (PET) depolymerization in supercritical methanol was investigated to develop a chemical recycling process for postconsumer PET bottles. PET with a high molecular weight (IV value (intrinsic viscosity) = 0.84) was depolymerized in a batch reactor at temperatures between 543…
Unusual scattering effects from tiny spherical particles may be obtained when concentric shells are designed by pairing together “complementary” double-negative, single-negative, and∕or standard double-positive materials. By embedding these highly polarizable scatterers in a host medium one can achieve a bulk medium w…
Doughnut-shaped ZnO microparticles have been grown through a hydrothermal reaction in citrate solution at 120 degrees C. FESEM reveals that these microparticles consist of regular arranged nanoplates, and there is a concave on the surface of each microparticle. The existence of citrate is vital to the formation of the…
Single crystals of the layered perovskite $\mathrm{Gd}\mathrm{Ba}{\mathrm{Co}}_{2}{\mathrm{O}}_{5+x}$ (GBCO) have been grown by the floating-zone method, and their transport, magnetic, and structural properties have been studied in detail over a wide range of oxygen contents $0\ensuremath{\leqslant}x\ensuremath{\leqsl…
Single- and multiwalled carbon nanotubes have been covalently functionalized with free-base porphyrin. The quantity of porphyrin linked to the surface was determined from thermogravimetric and UV-vis analysis. A reversible protonation equilibrium between the attached porphyrin and the residual acid groups of the carbo…
Chitosan films were plasticized with four hydrophilic compounds, namely, glycerol (GLY), ethylene glycol (EG), poly(ethylene glycol) (PEG), and propylene glycol (PG). Our objective was to investigate the effect of plasticizers on mechanical and surface properties of chitosan films. The stability of plasticized films w…
To investigate the failure of the poly(dimethylsiloxane) polymer (PDMS) at high temperatures and pressures and in the presence of various additives, we have expanded the ReaxFF reactive force field to describe carbon-silicon systems. From molecular dynamics (MD) simulations using ReaxFF we find initial thermal decompo…
Internal stress and yield strength of pure copper films on substrates were characterized by x-ray diffraction and thermal-cycle substrate curvature methods. The internal stress was of tension and decreased with increasing working-gas (argon) pressure and increased with increasing film thickness. Tensile yield strength…
Ni(II)-2-Vinyl-5,10,15,20-tetraphenylporphyrin reacts with 1,4-naphthoquinone and 1,4benzoquinone to afford mixtures of rigid porphyrin-quinone derivatives with extended systems. The structures of these novel compounds were deduced from detailed NMR experiments.
Structural and electronic properties of (100)-oriented MgSO(4) and MgSO(4).H(2)O surfaces and the adsorption of water on the latter were investigated theoretically with a combination of ab initio and semiempirical methods. Ab initio electronic structure calculations were based on a density functional theory (DFT)-Hart…
We have investigated surface vibrations generated by ultrasound excitation of individual unencapsulated micron-sized bubbles. In addition, we present surface modes (n=2 and 3) observed for phospholipid-coated ultrasound contrast agents excited through excitation of radial modes at frequencies between 1 and 4 MHz. Even…
Unrelaxed energies for Cu (001) twist grain boundaries (GBs) are calculated using a Modified Analytical Embedded Atom Method (MAEAM). The results show that, except zero energy at 0 degrees (perfect crystal), a small cusp exists at a twist angle of 36.87 degrees corresponding to Σ = 5, which agrees with experimental re…
We investigate by rheology and light scattering the influence of the elastic modulus, G0, on the slow dynamics and the aging of a soft glass. We show that the slow dynamics and the aging can be entirely described by the evolution of an effective viscosity, eta(eff), defined as the characteristic time measured in a str…
In a search for effective polymer film material for holographic surface patterning, commercially available azobenzene polyelectrolyte has been employed. Films of good optical quality in a wide range of thickness were produced. Optical dichroism up to 0.19 was induced upon irradiation with linearly polarized light. Sur…
The performances of minimum-size copper and carbon nanotube interconnects are compared for various ITRS generations. Results offer important guidance regarding the nature of carbon nanotube technology development needed for improving interconnect performance. Since wave propagation is slow in a single nanotube, nanotu…
The resonance frequencies of individual SonoVue/spl trade/ contrast agent bubbles were measured optically by recording the radius-time curves of a single microbubble at 24 different frequencies. For these experiments, the Brandaris 128 fast framing camera was operated in a special segmented mode. The resonance frequen…
An investigation of plasma chemistry for dc plasma enhanced chemical vapour deposition of carbon nanotubes and nanofibres, Hash, David B, Bell, Martin S, Teo, Kenneth B K, Cruden, Brett A, Milne, William I, Meyyappan, M
Sintering of ZnO pressed powder under Ar flow at temperatures between 1250 and 1300 °C leads to the formation of elongated microstructures and nanostructures, with different morphologies, on the sample surface. Rods and needles with cross-sectional dimensions ranging from tens of nanometres to several tens of microns…
Thermodynamic and neutron-diffraction measurements combined with molecular dynamics simulation are used to determine the adsorption energies and the structure of argon condensed in the various adsorption sites of purified open-ended single-wall nanotube bundles. On the basis of these experiments and the simulation res…