Materials Literature
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A procedure has been developed which utilizes aminopropyltriethoxysilane (APS) as the catalyst and a comonomer in the production of hybrid organo‐silica nanoparticles. Particles ranging from ca. 100 to 500 nm can be prepared using organo‐silanes of the type R′Si(OR) 3 , where R′= Me, vinyl, allyl, or other hydrophobic…
Transparent conducting films comprised of ZnO and ZrO2, with ZrO2 content varying between 0 and 10 wt %, have been deposited using pulsed-laser deposition. These films have resistivities ranging between 5.4×10−4 and 5.6×10−2 Ω cm with an optical transparency of more than 85% for the 250–900-nm-wavelength range. For fi…
Phosphorus-containing dendrimers of first, second, and third generation with various peripheral functional groups and bearing a hydrolyzable Si(OEt) 3 group at the core have been prepared. Two synthetic routes were used: either the Si(OEt) 3 group was introduced from the start by reaction of (EtO) 3 Si(CH 2 ) 3 PPh 2…
X-ray diffraction analysis of protein structure is often limited by the availability of suitable crystals. However, the absence of single crystals need not present an insurmountable obstacle in protein crystallography any more than it does in materials science, where powder diffraction techniques have developed to the…
X-ray photon correlation spectroscopy and small-angle x-ray scattering measurements are applied to characterize the dynamics and structure of concentrated suspensions of charge-stabilized polystyrene latex spheres dispersed in glycerol, for volume fractions between 2.7% and 52%. The static structures of the suspension…
Fluorinated aliphatic polyurethanes based on hexamethylene diisocyanate (HDI) and polytetramethyl oxide (PTMO) were synthesized by using 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol (OF) or 2,2,3,3-tetrafluoro-1,4- butanediol (TF) as a chain extender. The polyurethanes chainextended with 1,4-butanediol (BD) were also pre…
The crystal structure of the third polymorph of the Cu(7)PSe(6) argyrodite compound, alpha-Cu(7)PSe(6), heptacopper phosphorus hexaselenide, is determined by means of single-crystal diffraction from twinned crystals and X-ray powder diffraction, with the help of extensive NMR measurements. In the low-temperature form,…
Thirty eight compounds composed of achiral banana-shaped molecules belonging to three new homologous series have been synthesized and their mesomorphic properties investigated. The mesophases have been characterized using a combination of polarized light microscopy, differential scanning calorimetry, miscibility metho…
The structural changes of rectorite Rar-1 during dehydroxylation have been studied using Infrared Emission Spectroscopy and have been compared to the changes observed for synthetic beidellite and paragonite. The hydroxyl-stretching region is characterised in all cases by a band around 3,640-3,650cm assigned to H-bonde…
The use of biodegradable nanoparticles loaded with 5-fluorouracil was investigated as a potential means to sustain the release of this drug. Nanoparticles prepared from four biodegradable polymers were loaded with 5-fluorouracil using three loading concentrations of drug and three different concentrations of added pol…
Abstract Infrared spectroscopy in the mid-IR region was used to follow the structural changes occurring in five Li-saturated dioctahedral smectites upon heating. The smectites included three montmorillonites, an Fe-beidellite and a ferruginous smectite. Fixation of Li + ions in the structure even upon heating at 120°C…
The crystallization and dielectric properties of SrO–BaO–Nb 2 O 5 –SiO 2 glass‐ceramics have been investigated. Glass‐ceramics that contain strontium barium niobate (SBN) as a primary crystalline phase, which has a tungsten bronze structure, are produced. The formation of crystalline secondary phases also has been stu…
The self-nucleation of branched polyethylene chains of different degrees of chain mobility was studied. The polyethylene block (PE block) within poly(styrene-b-ethylene-b-caprolactone) triblock copolymers (SEC) of varying compositions was studied. Differential scanning calorimetry was used to determine the self-nuclea…
The phase behavior of rod−plate mixtures was investigated using model systems of unambiguously rod- and plate-shaped colloids. Neither at equilibrium nor in the early stages of the phase separation process do we observe the theoretically disputed biaxial nematic phase. Instead, the mixtures show demixing into an isotr…
ZnO thin films have been grown on various substrates by femtosecond pulsed-laser deposition. According to optical microscopy and atomic force microscopy analyses, the production of droplets is not significant using femtosecond pulses. Smooth, dense, stoichiometric, crystalline, and textured hexagonal ZnO films are epi…
We present a model to more accurately describe the optical properties of a twisted nematic liquid crystal display (LCD). In particular, we study the optical properties of molecules near either edge of the LCD that are unable to twist and tilt under the application of an external elec- tric field. The properties of the…
Composite materials such as clay sheets intermixed with polymershave important potential applications; however, some fundamental properties remain to be understood. The equilibrium phase behavior of polymer–clay nanocomposites is examined here. The authors build on their recently proposed model that combines self-cons…
Phosphino carboxylic acid ester terminated G(0) compounds Si(CH(2))(3)SiMe(2)(C(6)H(4)CH(2)OC(O)(CH(2))(n)()CH(2)PPh(2)(4) (9a and 9b; n = 1, 2) and the carbosilane dendrimers Si(CH(2))(3)Si((CH(2))(3)SiMe(2)(C(6)H(4)CH(2)OC(O)(CH(2))(n)()CH(2) PPh(2))(3)(4) (10a and 10b; n = 1, 2) have been prepared as hemilabile nan…
Highly organized and textured CTAB templated silica films are made by the spin-coating technique. The HRTEM structural characterization of these films clearly shows the formation of a 3D hexagonal structure ( P 6 3 / mmc space group) due to the stabilization of a new phase which does not belong to the phase diagram of…
Hybrid organic−inorganic proton conducting gels (PWA/ICS−PPG or SiWA/ICS−PPG) were made from 3-isocyanatopropyltriethoxysilane and poly(propylene glycol)bis(2-aminopropyl ether), resulting in a hybrid silicon precursor (ICS−PPG) in which was dispersed phosphotungstic acid (PWA) or silicotungstic acid (SiWA) in ethanol…