Materials Literature
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We performed a systematic measurement of the dielectric function of Si nanoslabs as a function of their thickness using spectroscopic ellipsometry from $0.73\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ $(1700\phantom{\rule{0.3em}{0ex}}\mathrm{nm})\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}4.58\phantom{\…
AIMS: Magnetic nanoparticles have been studied widely as MRI contrast agents to increase the sensitivity of this technique. This work describes the synthesis and characterization of magnetic nanotubes (MNTs) as a novel MRI contrast agent. METHODS: MNTs with high saturation magnetization were fabricated by the synthesi…
We compare the photochemical stability of the nonlinear optical chromophore configurationally locked polyene 2-{3-[2-(4-dimethylaminophenyl)vinyl]-5,5-dimethylcyclohex-2-enylidene} malononitrile (DAT2) embedded in a polymeric matrix and in a single-crystalline configuration. The results show that, under resonant light…
A new, high strength (2.4 GPa) polycrystalline alumina fiber has recently been developed at 3M (trade name Nextel 610). The high temperature creep properties and creep rupture mechanisms were determined in the temperature range 900°C −1200°C. The creep rate was proportional to the cube of stress and was controlled by…
Abstract Electrocopolymerization of 3,4‐ethylenedioxythiophene (EDOT) and 5‐methylindole (5MeIn) was successfully carried out in acetonitrile containing lithium perchlorate as supporting electrolyte although the oxidation potentials of 5MeIn and EDOT were quite different. The influence of feed ratios and applied poten…
Ion-promoted, automorphogenic, and stoichiometric self-assembly of a hexameric, Ru-based macrocycle and a dendrimer produces a stable nanofiber. A structurally related larger 3rd generation dendrimer was reacted with [(112+)(PF6−)12] to afford a neutral, sphere-like motif. These polyanionic counterions lead to ion-pai…
We discuss simulations of a simple model for polymer blends in the framework of the Rouse model. At odds with standard predictions, large dynamic asymmetry between the two components induces strong nonexponentiality of the Rouse modes for the fast component. Despite chains being much shorter than the entanglement leng…
In Archaea, acetate formation and ATP synthesis from acetyl-CoA is catalyzed by an unusual ADP-forming acetyl-CoA synthetase (ACD) (acetyl-CoA + ADP + P(i) acetate + ATP + HS-CoA) catalyzing the formation of acetate from acetyl-CoA and concomitant ATP synthesis by the mechanism of substrate level phosphorylation. ACD…
Biological passivation of porous silicon (PSi)-based optical devices is demonstrated. Infiltration by small amphiphilic fungal proteins called HFBs changes the wettability of the PSi surface (see figure) and protects the sponge-like structure against dissolution by basic solutions. This protein membrane leaves the sen…
Based on perturbation theory and local-density-functional calculations, we study the effect of atomic-scale defects, whose potentials vary on the scale of interatomic distance, on the electronic structure of graphene in the region of low energies. If defects are identical, for example, vacancies at the same sublattice…
Polymers represent the largest and versatile class of biomaterials being extensively applied in multitude of biomedical applications. This versatility is attributed to the relative ease with which polymers can be designed and prepared with a wide variety of structures and appropriate physical, chemical, surface and bi…
Abstract Silica‐reinforced natural rubber (NR) composite was prepared by using tetraethoxysilane (TEOS) as a precursor to generate silica particles inside the rubber. The silica was generated in situ by the sol–gel process of TEOS that was mixed directly into commercial‐graded NR latex having 60% dry rubber content an…
The magnetization reversal mechanism in pulsed laser deposited, hard magnetic epitaxial $\mathrm{Sm}{\mathrm{Co}}_{5}$ thin films with high coercivity $(>3\phantom{\rule{0.3em}{0ex}}\mathrm{T})$ and remanent polarization $(0.94\phantom{\rule{0.3em}{0ex}}\mathrm{T})$ is investigated. From temperature and angle depen…
Multifunctional materials such as mag netoelect rics can be used in novel device applications. Magnetism and ferroelectricity coexist in some materials, but the coupling between them is very small to use them in devices. Using density function al calculations we have shown that BiCoO3 (see figure) has large magneto-el…
We evaluate explicit atom, united atom, and coarse-grained force fields for molecular dynamics simulation of poly(methyl methacrylate) (PMMA) by comparison to structural and dynamic neutron scattering data. The coarse-grained force field is assigned based on output of the united atom simulation, for which we use an ex…
The recycling process of polypropylene (PP) and the elaboration of recycled polypropylene/modified clay nanocomposite by melt intercalation method have been investigated. The purpose of this work is to characterize the influence of the recycle processing of an homopolypropylene on the mechanical, thermal, and rheologi…
Proximity of fluorescent molecules to noble metal nanoparticles leads to a strong enhancement of the fluorescent intensity during irradiation with light, a consequence of resonant coupling to localized particle plasmons. In this communication we show that the substrate can have a profound effect on this simple picture…
Abstract A novel polyhedral oligomeric silsesquioxane (POSS) containing a mercaptopropyl group [mercaptopropyl polyhedral oligomeric silsesquioxane (MPOSS)] was synthesized via the hydrolytic condensation of γ‐mercaptopropyl triethoxysilane in an ethanol solution catalyzed by concentrated hydrochloric acid and was use…
We report on a study of the influence of a magnetic field on the nematic phase and the isotropic-to-nematic (IN) phase transition of hard colloidal gibbsite platelets. We find direct visual evidence of a shift of the IN transition to lower concentrations due to the magnetic field. The nematic phase readily aligns when…
Powders of roller quenched (Sr,Ba)O·Al2O3·2SiO2 glasses of various compositions were uniaxially pressed into bars and hot isostatically pressed at 1350°C for 4 h or cold isostatically pressed and sintered at different temperatures between 800° to 1500°C for 10 or 20 h. Densities, flexural strengths, and linear thermal…