Materials Literature
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Stable, carbon nanotori can be constructed from nanotubes. In theory, such rings could be used to fabricate networks that are extremely flexible and offer a high strength-to-density ratio. As a first step towards realizing such nanochains and nanomaile, the mechanical properties of connected carbon nanorings were inve…
Near-infrared emitting complexes of Nd(III), Er(III), and Yb(III) based on hexacoordinate lanthanide ions with an aryl functionalized imidodiphosphinate ligand, tpip, have been synthesized and fully characterized. Three tpip ligands form a shell around the lanthanide with the ligand coordinating via the two oxygens le…
We describe a new electrochemical synthetic method and characterization of poly(3,4-ethylenedioxythiophene) (PEDOT) nanotubes in a polycarbonate membrane. The very thin nanotubular structures in the highly flexible template provide fast electrochromic response (20 ms for oxidation or decoloration) even in a rolled sta…
Morphological features governing dimensional stability of variously processed poly(lactic acid) have been investigated. The exotherm observed near the glass transition temperature ( T g ) is one of the most sensitive indicators reflecting structural changes as a function of temperature and time. A combination of spect…
The present work deals with the effects of structural variables of celluloses on their dissolution in the solvent system LiCl/N,N-dimethylacetamide, LiCl/DMAc. Celluloses from fast growing sources (sisal and linters), as well as microcrystalline cellulose (avicel PH-101) were studied. The following structural variable…
Abstract Dispersion and exfoliation of single wall carbon nanotubes (SWNTs) have been studied in poly(acrylonitrile) (PAN), poly( p ‐phenylene benzobisoxazole) (PBO) solutions, and composite fibers using transmission electron microscopy. As a result of polymer assisted dispersion and exfoliation, the average SWNT bund…
A thermally stable, hierarchically porous zirconia material is synthesized using a composite template of block copolymer and surfactant. The zirconia has a high surface area, a nanocrystallized framework, a well-defined one- dimensional macroporous structure, and a very uniform mesopore distribution (see Figure).
We present a simple, wet-chemical method for fabricating linear chains of Au and Ag nanoparticles by selectively etching alternating segments from striped metal nanowires. Nanowires composed of sacrificial Ni segments as well as Au and/or Ag segments were prepared by templated electrodeposition in the pores of alumina…
A Kondo-like transport was observed in a metal-semiconductor transition (MSC) at low temperatures in the ferromagnetic metallic phase of the perovskite manganites. Experimental data can be best fitted in the framework of Kondo scattering, electron-electron $(e\text{\ensuremath{-}}e)$, and electron-phonon $(e\text{\ens…
Abstract Epoxy‐clay nanocomposites were synthesized to examine the effects of the content and type of different clays on the structure and mechanical properties of the nanocomposites. Diglycidyl ether of bisphenol‐A (epoxy) was reinforced by 0.5–11 wt % natural (Cloisite Na + ) and organically modified (Cloisite 30B)…
Abstract Nanocomposites based on atactic polypropylene (aPP) and multiwall carbon nanotubes were prepared by melt blending at 80°C with a Barabender mixer. The morphology, thermal stability, and dynamic mechanical properties of the obtained composites were studied subsequently. SEM observations indicate that the nanot…
The response of a neo-Hookean fiber composite undergoing finite out-of-plane shear deformation is examined. To this end an explicit close form solution for the out-of-plane shear response of a cylindrical composite element is introduced. We find that the overall response of the cylindrical composite element can be cha…
A c($3\sqrt{2} \times \sqrt{2}$) reconstructed structure of the Fe(001) surface with self-assembled C zigzag chains has been recently observed experimentally. Using ab initio density-functional calculations, we address the effect of the C zigzag chains on the electronic structure of this surface. We find that the form…
Density functional theory calculations have been performed to obtain lattice parameters, elastic constants, and electronic properties of ideal pyrochlores with the composition ${A}_{2}{B}_{2}{\mathrm{O}}_{7}$ (where $A=\mathrm{La}$,Y and $B=\mathrm{Ti}$,Sn,Hf,Zr). Some thermal properties are also inferred from the ela…
Highly faceted wurtzite-type ZnS nanotubes with hexagonal cross-sections have been self-assembled via a thermochemistry process. The self-assembled growth along the c-axis is associated with the non-central and polar surfaces of the ZnS structure (see Figure and inside cover). Photoluminescence at room temperature sho…
Grazing incidence anomalous x-ray scattering was used to monitor in situ the molecular beam epitaxy growth of GaN/AlN quantum dots (QDs). The strain state was studied by means of grazing incidence Multi-wavelength Anomalous Di raction (MAD) in both the QDs and the AlN during the progressive coverage of QDs by AlN mono…
Abstract Unsaturated polyester and epoxy resin matrices were filled with silane‐treated cellulose fibers and the ensuing composites were tested in terms of mechanical properties before and after accelerated aging consisting of their immersion into water. The coupling agents used were γ‐aminopropyltriethoxysilane (APS)…
Multimillion-atom molecular dynamics simulation of indentation of nanocrystalline silicon carbide reveals unusual deformation mechanisms in brittle nanophase materials, resulting from the coexistence of brittle grains and soft amorphous grain boundary phases. Simulations predict a crossover from intergranular continuo…
Percolation is a statistical concept that describes the formation of an infinite cluster of connected particles or pathways. Lowering the percolation threshold is a critical issue to achieve light and low-cost conductive composites made of an insulating matrix loaded with conductive particles. This has interest for ap…
There have been long-standing concerns about the stability of the internal structure of nanocrystalline metals. In this letter we examine grain growth in nanocrystalline Cu under the microhardness indenter, examining the influence of temperature of indentation and sample purity. Surprisingly, it is found that grain co…