Materials Literature
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We report a generalized scenario for the formation of modulated smectic phases of bent-core molecules based on locally ferroelectric layering and spontaneous splay of the polarization. Twelve phases are proposed, distinguished by neighboring splay stripes with either syn- or antiorder of the polarization and undulatio…
Abstract The effects of extrusion conditions on the mechanical properties of recycled poly(ethylene terephthalate) (rPET)/clay nanocomposites were studied. Nanocomposites of recycled PET containing 2.5 and 5.0 wt % of montmorillonite modified with organophilic quaternary ammonium salt (DELLITE 67G) were prepared by me…
Extended x-ray absorption fine structure has been measured on two powdered samples of (70)Ge and (76)Ge as a function of temperature from 20 to 300 K. The effect of isotopic mass difference on the amplitude of relative atomic vibrations is neatly evidenced by the temperature dependence of the difference of Debye-Walle…
We produced large binder-free multi-walled carbon nanotube (MWNT) blocks from fluorinated MWNTs using thermal heating and a compressing method in vacuo. This technique resulted in the formation of covalent MWNT networks generated by the introduction of sp(3)-hybridized carbon atoms that cross-link between nanotubes up…
Over the last 12 years, the possible existence of a tetrahedratic mesophase, involving a third-rank orientational order parameter and no positional order, has been addressed theoretically and predicted in some cases; no experimental realizations of a purely tetrahedratic phase are known at the time being, but various…
We report the first direct observation of the influence of high magnetic fields on the Jahn-Teller (JT) transition in TbVO(4). Contrary to spectroscopic and magnetic methods, x-ray diffraction directly measures the JT distortion; the splitting between the (311)/(131) and (202)/(022) pairs of Bragg reflections is propo…
Multiple-protein delivery has been proven to be a critical consideration for promoting tissue regeneration. Many polymeric composite biomaterials have been designed and used for modulating dual-protein delivery to enhance tissue regeneration in vitro or in vivo. However, the fabrication conditions and low water conten…
A series of lanthanide-containing macrocycles, Eu2-Eu5, exhibited unique luminescent responses in the presence of strong hydrogen-bond-accepting anions (F-, CH3COO-, and H2PO4-) in dimethyl sulfoxide. The macrocycles examined herein were designed to include a lanthanide chelate, aromatic spacers that function as anten…
Vanadium pentoxide (V 2 O 5 ) nanorods and nanotips have been grown without a catalyst by a thermal deposition method using compacted V 2 O 5 powder as the starting material. The tips, with diameters of about 50–100 nm, grow on the top of rods of larger size. Transmission electron microscopy shows that the obtained st…
The relaxation dynamics of unsubstituted porphyrin (H2P), diprotonated porphyrin (H4P2+), and tetraoxaporphyrin dication (TOxP2+) has been investigated in the femtosecond-nanosecond time domain upon photoexcitation in the Soret band with pulses of femtosecond duration. By probing with spectrally broad femtosecond puls…
A hybrid mesoporous membrane is developed by forming surfactant-templated mesoporous silica inside columnar alumina pores of an alumina membrane. Predominant formation of one-dimensional silica nanochannels (channel diameter = 8 nm) is achieved by controlling the aging time and temperature for preparation of the precu…
Edible films made of iota-carrageenans display interesting advantages: good mechanical properties, stabilization of emulsions, and reduction of oxygen transfers. Moreover, the addition of lipids to iota-carrageenan-based films to form emulsified films decreases the transfer of water vapor and can be considered to enca…
We report on the structural characterization of amyloid-like fibrils, self-assembled from synthetic polypentapeptides poly(ValGlyGlyLeuGly), whose monomeric sequence is a recurring, simple building block of elastin. This polymer adopts a beta-sheet structure as revealed by circular dichroism and Fourier transform infr…
We found that by fluorination of double-walled carbon nanotubes (DWNTs), it is possible to suppress only the Raman radial breathing mode and absorption peaks from the outer (large diameter) tubes of DWNTs. In contrast, Raman signals from the inner shells showed no difference from the pristine DWNTs. The stability of t…
The magnetic-field dependence of the ferroelectric polarization and the spin-lattice coupling in multiferroic $\mathrm{Mn}\mathrm{W}{\mathrm{O}}_{4}$ have been investigated. The ferroelectric transition from the low temperature paraelectric phase occurs when the magnetic field is applied along the $a$, $c$, and the sp…
Abstract The flammability behavior of the system polyamide 6 (PA 6) + melamine cyanurate (MC) with or without organically modified layered montmorillonite (OMMT) or sodium montmorillonite (Na + MMT) was studied. The high degree of flame retardancy (FR) obtained with 13 wt% MC is maintained upon adding up to 0.2 wt% OM…
The ferroelectric $E\text{\ensuremath{-}}T$ phase diagram of relaxor ferroelectrics depends on the way the ferroelectric transition lines are approached. Here, we present the $E\text{\ensuremath{-}}T$ phase diagram of relaxor $\mathrm{Pb}({\mathrm{Mg}}_{1∕3}{\mathrm{Nb}}_{2∕3}){\mathrm{O}}_{3}$ where the temperature w…
We have studied the electronic properties and the band structure of copper nanowires for various diameters using first principles density functional methods and a supercell approach. The resistances of copper nanowires were computed on the basis of the Landauer formalism and compared with those obtained from an empiri…
Using neutron scattering techniques, we have investigated spin wave excitations in noncollinear ferrimagnetic spinels $\mathrm{Mn}{B}_{2}{\mathrm{O}}_{4}$ $(B=\mathrm{Mn},\mathrm{V})$ with ${e}_{g}$ and ${t}_{2g}$ orbital degeneracies, respectively, that lead to tetragonal distortions along opposite directions. Linear…
A series of POSS (PEG) n =2-6 macromonomers were further functionalized by reaction with methacryloyl chloride and then polymerized with methyl methacrylate to produce a series of hybrid materials where the amounts of POSS (PEG) n =2-6 used as cross-linkers varied from 0.1 to 0.5 mol %. Thermal investigations using TG…