Materials Literature
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Abstract To compare the properties of hyperbranched polymers with linear oligomers for preparing organic‐inorganic hybrids, hyperbranched aliphatic polyester (Boltorn TM H20) and linear polyester hexa‐acrylate (EB830) were selected as organic components for preparing UV‐curable transparent hybrid materials using 3‐(tr…
Abstract Novel phosphazene cyclomatrix network polymers were synthesized via nucleophilic displacement of activated nitro groups of tri(4‐nitrophenoxy)tri(phenoxy)cyclotriphosphazene and hexa( p ‐nitrophenoxy)cyclotriphosphazene with the hydroxyls of bisphenol A. Both the monomers and polymers were characterized by Fo…
Abstract Energy‐transfer processes in phenylene‐based materials are studied via two different approaches: i) the original Förster model, which relies on a simple point‐dipole approximation; and ii) an improved Förster model accounting for an atomistic description of the interacting chromophores. Here, to illustrate th…
Results of isothermal magnetization and magnetic relaxation measurements are presented probing the nature of the magnetic-field-induced magnetostructural transition in the intermetallic compound ${\mathrm{Gd}}_{5}{\mathrm{Ge}}_{4}$. This transition shows the characteristics of a disorder-influenced first order transit…
A general synthetic method for the preparation of nanostructured materials with large surface area was developed by using nanoparticle building blocks. The preparation route involves the self-assembly of functionalized nanoparticles in a liquid-crystal phase. These nanoparticles are functionalized by using difunctiona…
Abstract Complexation reactions of titanium tetraethoxide [Ti(OEt) 4 ] and titanium tetra‐ n ‐butoxide [Ti(OBu n ) 4 ] with 3‐pentenoic acid (PA) and allylacetoacetate (AAA), in a 1 : 1 M ratio, were studied in ethanol solution at room temperature. 13 C‐NMR and FTIR spectra showed that all PA and AAA completely reacte…
Abstract Polyaniline or polypyrrole composites with fir or oak wood have been prepared by in situ polymerization of the corresponding monomers in an aqueous suspension of wood sawdust. The percolation threshold of compressed coated particles is located below 5 wt % of the conducting component and, above this limit, th…
Colloidal aqueous suspensions of goethite lath-shaped nanorods form nematic and isotropic phases. We show that they also display a 2D rectangular (c2mm) columnar phase at volume fractions phi larger than 15%. Interestingly, the nematic-columnar first-order transition can also be triggered by applying to the nematic ph…
Three methods were investigated for their suitability for the activation of poly(ethylene glycol) 2000 mono-methyl ether en route to conjugation with dendrimers, using 4-nitrophenylchloroformate as the activator. The use of acetonitrile as a solvent gave the best results. Poly(ethylene glycol) (PEG) grafted polyamidoa…
Abstract Bis(3‐thienyl)perfluorocyclopentenes containing partially fluorinated thiophene rings were synthesized and their behaviors examined. Dithienylethenes containing chlorinated thiophene rings were also prepared as reference compounds. The absorption maxima of the closed‐ring isomers, their thermal stabilities, a…
The influence of $A$ site disorder on the magnetic and transport properties of ${\mathrm{Pr}}_{0.6}{R}_{0.1}{\mathrm{Sr}}_{0.3}\mathrm{Mn}{\mathrm{O}}_{3}$ ($R=\mathrm{Tb}$, Y, Ho, and Er) polycrystalline samples is analyzed within the context of percolative transport and the existence of the Griffiths phase. The temp…
Here we report the synthesis and characterization of a new class of nanocomposite by direct in situ oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) with VS2 as a host material in the presence of an external oxidizing agent. Upon intercalation, the interlayer spacing of VS2 expands from 5.71 Å to 14.01 Å,…
The principal derivative of chitin is chitosan, which is obtained by deacetylation of chitin. Chemical modification of synthetic and natural polymers is a convenient way to obtain materials with unique chemical and physical properties. Chitosan has an amino group at C-2 which is important because amino groups are nucl…
A synthetic method that can fine tune the amount of chemically accessible organic functional groups on the pore surface of MCM-41 type mesoporous silica nanosphere (MSN) materials has been developed by electrostatically matching various anionic organoalkoxysilanes with the cationic cetyltrimethylammonium bromide micel…
Abstract Three systematically functionalized pyrrolide ligands were prepared via the coupling of methyl vinyl ketone and the respective carbaldehyde reagents, followed by treatment of the pre‐formed dicarbonyl compounds with (NH 4 ) 2 CO 3 in order to generate the required pyrrole fragment. These ligands readily react…
The hole distribution in a double quantum well (QW) structure consisting of a magnetic and a nonmagnetic semiconductor QW is investigated as a function of temperature, the energy shift between the QWs, and other relevant parameters. When the itinerant holes mediate the ferromagnetic ordering, it is shown that a bistab…
A most basic and puzzling enigma in surface science is the description of the dissociative adsorption of O2 at the (111) surface of Al. Already for the sticking curve alone, the disagreement between experiment and results of state-of-the-art first-principles calculations can hardly be more dramatic. In this paper we s…
We study the effects of the presence of contrarians in an agent-based model of competing populations. Contrarians are common in societies. These contrarians are agents who deliberately prefer to hold an opinion that is contrary to the prevailing idea of the commons or normal agents. Contrarians are introduced within t…
We calculate the ground-state energy of one and two-dimensional spatially inhomogeneous antiferromagnetic Heisenberg models for spins 1/2, 1, 3/2 and 2. Our calculations become possible as a consequence of the recent formulation of density-functional theory for Heisenberg models. The method is similar to spin-density-…
We report on a study of the ac conductivity and magneto-optical properties of metallic ferromagnetic (III, Mn)V semiconductors in the infrared to visible spectrum at zero temperature. Our analysis is based on the successful kinetic exchange model for (III, Mn)V ferromagnetic semiconductors. We perform the calculations…