Materials Literature
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A discrete phenomenological model of antiferroelectric liquid crystals is used to study the structures and phase transitions in bulk samples and thin films. An important ingredient of our investigations is minimization of the free energy with respect to the phase and modulus of the order parameter. A simple version of…
Abstract We have synthesized polyethoxysiloxanes starting from the AB 3 ‐type monomers triethoxysilanol and acetoxytriethoxysilane. The polymers are liquid and soluble in organic solvents. 29 Si NMR spectroscopy and MALDI‐ToF mass spectrometry analyses show that the polymers have a hyperbranched structure with additio…
The photomagnetic properties of CoFe Prussian blue analogues arise from a photoinduced Co III (LS)−Fe II (LS) → Co II (HS)−Fe III (LS) [LS = low spin, HS = high spin] electron transfer accompanied by a spin state change of the cobalt and a significant expansion of the cobalt coordination sphere. The local bond-lengthe…
Zinc(II) phthalocyanines 4 and 5 decorated with six optically active alkyl chains and one chial diol were synthesized from two phthalonitriles using mixed tetramerization reactions. The self-organizing properties of these complexes and related compounds 3, 6, and 7 in CHCl 3 solution and thin film were studies by UV−v…
Abstract The crystallization behavior of pure nylon 6 (N6) and its nanocomposite with montmorillonite has been studied in detail. The crystallization rate of N6 is faster in the presence of clay compared to pure N6, as revealed by light scattering experiments. Nylon 6 crystallizes exclusively in the γ ‐form in the nan…
We study the stress response to a steady imposed shear rate in a concentrated suspension of colloidal particles. We show that, in a small range of concentrations and shear rates, stress exhibits giant fluctuations. The amplitude of these fluctuations obeys a power-law behavior, up to the apparition of a new branch of…
Abstract The theory of size effects in nanocrystalline ferroelectric ceramics or nanoparticle powders allowing for surface tension and depolarization field is proposed. Surface tension was included in the free energy functional and extrapolation length was expressed via surface tension coefficient. The latter was show…
The photochemistry, electrochemistry, and electrogenerated chemiluminescence (ECL) of five boron-based laser dyes (BODIPY, PM 546, PM 567, PM 580, PM 597) have been investigated. These show high fluorescence quantum yields (Φ > 0.85) for all dyes except PM 597 (Φ ≈ 0.41), because of the high degree of substitution and…
We study the morphological evolution of surfaces during ion sputtering and we compare their dynamical roughening with aeolian ripple formation in sandy deserts. We show that the two phenomena can be described within the same theoretical framework. This approach explains the different dynamical behaviors experimentally…
The local atomic order of an amorphous Ga$_{50}$Se$_{50}$ alloy produced by Mechanical Alloying (MA) was studied by the Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Diffraction (XRD) techniques and by Reverse Monte Carlo (RMC) simulations of its total x-ray structure factor. The coordination numbers and…
The properties of the contacts between single-walled carbon nanotubes (SWNTs) and Au electrodes are studied using scanning Kelvin probe and electrostatic force microscopies. Contact potential differences and local dipoles at the SWNT/Au interface are determined under various conditions involving gas adsorption and sur…
Gold is not as noble as it is widely assumed—at least in the form of nanostructured gold clusters or the depicted multiwalled nanotubes. Recent progress shows the potential use of such structures, for example, in catalysis, molecular electronics, or as bioconjugate probes for gene analysis.
An organic−inorganic hybrid heterogeneous catalyst system was synthesized by covalently anchoring oxodiperoxo molybdenum complexes [(L−L)MoO(O 2 ) 2 ] (L−L = (3-triethoxysilylpropyl)[3-(2-pyridyl)-1-pyrazolyl]acetamide) onto the mesoporous silica MCM-41 (Si−MCM-41) and aluminosilicate MCM-41 (Al−MCM-41) materials. Cha…
Electron-lattice energy exchanges are investigated in gold and silver nanoparticles with sizes ranging from 30 to 2.2 nm embedded in different environments. Femtosecond pump-probe experiments performed in the low-perturbation regime demonstrate a strong increase of the intrinsic electron-phonon interaction for nanopar…
Poly(amidoamine) (PAMAM) dendrimers of generations G0, G1, G2, G3, G4, and G6 are investigated by potentiometric (acid−base) titrations. The data are interpreted with a site binding model, which offers the possibility to model the titration curves for all generations of the dendrimers and to describe all dendrimers wi…
Titania/polymer capsules and hollow titania spheres are prepared by using sulfonated-polystyrene core–shell gel particles as templates. The titania shell thickness and the cavity size are controlled in the entire particle radius range. If an electric field is applied during synthesis, hollow spheres with pillared surf…
Abstract The growth process, stability of GaP nanocrystals and the formation of Ga 3 P nanocrystals under solvothermal conditions were investigated. At moderate reaction times and temperature, the growth process is mainly in accordance with the Ostwald ripening mechanism, which is the dissolving of the smaller GaP cry…
Abstract The dinucleating ligand 1,2‐bis(3,5‐di‐ tert ‐butyl‐2‐hydroxyphenyl)oxamide [H 4 (bbpo)] has been synthesized. From its reaction with GaCl 3 or FeCl 3 in CH 3 OH/NaOH the salts [N( n Bu) 4 ] 2 [M III 2 (bbpo)Cl 4 ] [M = Ga ( 1 ), Fe ( 2 )] have been isolated as crystalline solids upon addition of [N( n Bu) 4…
Abstract Theoretical methods based on density functional theory using hybrid functionals provide good estimates of the exchange coupling constants for complexes with metals of the second transition series, with accuracy similar to that previously obtained for complexes with lighter transition metals. The influence of…
A weak ferromagnetic phase is shown in pressed pellets of partially doped poly(3-methylthiophene) (P3MT) in the whole range from 1.8 to 300 K in magnetic measurements. Thermoremanence data have been used to estimate the suppression of this phase to be around 815 K. We also show that instead of the classical antiferrom…