Materials Literature
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We study the dynamics of a single Frenkel exciton in a disordered molecular chain. The coherent-potential approximation (CPA) is applied to the situation when the single-molecule excitation energies as well as the transition dipole moments, both their absolute values and orientations, are random. Such model is believe…
Phytochemical investigations on the aerial parts of Phlomis samia resulted in the isolation of a simple phenolic glucoside, 2,6-dimethoxy-4-hydroxyphenol-1-O-b -D-glucopyranoside (1); a megastigmane glucoside, phlomuroside (=3-hydroxy-5,6-epoxy-b -ionol-9-O-b -D-glucopyranoside) (2); and a nucleotide glycoside, uridin…
The barrier properties of edible films prepared from polysaccharide polymer (locust bean gum) and various plasticisers (glycerol, propylene glycol, sorbitol, and polyethylene glycol 200) together with hydrophobic modifiers (stearopten and beeswax) were examined. It was determined that the films containing polyethylene…
A kind of hybrid multilayer film based on mercaptobenzoic acid-capped Au nanoparticles (MBA-Au-NPs) and photoreactive nitrodiazoresin (NDR) has been fabricated via electrostatic self-assembly. Upon exposure to UV light, the initial ionic bonds between the layers of the film convert into covalent bonds and the film sta…
The synthesis of the green cyclopentadiene-fused dimethyldihydropyrene 12 was achieved in 36% yield in 7 steps from the parent dihydropyrene 3. Reaction of 12 with KH or LiCH(2)SiMe(3) gave the [14]annulene-fused cyclopentadienide anion quantitatively. In the (1)H NMR spectra, the internal methyl protons of 12 at delt…
We present the results of an experimental study on the solidification of aqueous solutions of potassium nitrate and sodium nitrate cooled from below. Upon cooling, two distinct mushy layers form, primary and cotectic, separated by an approximately planar horizontal interface. A density reversal between the two mushes…
Dendronized, hybrid dendritic−linear polymers were synthesized by either the “graft-onto” route or by atom transfer radical polymerization (ATRP) of macromonomers. In both ways, the main chain was composed of acrylate repeating units and the dendrons were based on the aliphatic ester skeleton obtained from 2,2-bis(met…
The present article describes the synthesis of the N-(Lys-Gly-Tyr-Gly)-chitosan using the water-soluble active ester method, the preparation of the N-(Lys-Gly-Tyr-Gly)-chitosan-gellan hybrid fibers, and the reinforcement of the hybrid fibers by enzymatic cross-linking between the N-grafted peptides chains of chitosan.…
Selectively deuterated, dodecyloxy substituted stilbenoid dendrimers of the first and second generation were synthesized by a convergent synthesis, using the Wittig-Horner reaction. The photochemistry and the fluorescence in the different crystalline and liquid crystalline phases were investigated. Molecules deuterate…
The modification of peripherally metalated meso -η 1 -platiniometalloporphyrins, such as trans -[PtBr(NiDAPP)(PPh 3 ) 2 ] (H 2 DAPP = 5-phenyl-10,20-bis(3‘,5‘-di- tert -butylphenyl)porphyrin), leads to the analogous platinum(II) nitrato and triflato electrophiles in almost quantitative yields. Self-assembly reactions…
By truncating the range of van der Waals forces in our molecular dynamics model we reduce the lengthscale and timescale gap between the outer (wedge) and inner (precursor) regions in droplet spreading simulations. This results in a molecular model which combines atomic-scale resolution with the ability to capture larg…
Thermal transition property of cellulose diacetate-graft-poly(L-lactide) (CDA-g-PLLA) varies depending seriously on the molar substitution (MS) of lactyl unit, as represented by a drastic Tg depression with increasing MS (0<MS< or =8) and a subsequent crystallization of the PLLA side chains (MS> or =14). To make clear…
Enzymatic hydrolysis of selected copolymers of cellulose diacetate-graft-poly(L-lactide)s (CDA-g-PLLAs) were conducted with proteinase K for film specimens, which were solely quenched from the molten state or, further, annealed at temperatures below or above their glass transition temperatures. The hydrolysis rates de…
Development of synthesis protocols for realizing nano-materials over a range of sizes, shapes and chemical compositions is an important aspect of nanotechnology. A number of recipes have been developed for the synthesis of metal nanoparticles in polar (for example, water) and non-polar organic solvents, each method ac…
Spherulites of poly(L-lactic acid) (PLLA) and of its blends with atactic poly(3-hydroxybutyrate) (a-PHB, from 10 to 75 wt %) were investigated by microfocus X-ray diffraction using synchrotron radiation. Radial scans in 5 microm steps with 3 microm beam diameter were performed. In PLLA, tens of identical diffraction i…
Water-soluble cellulose acetates with a degree of substitution (DS) of 0.5, prepared by partial deacetylation of cellulose acetate of DS=2.5, were oxidized with catalytic amount of 2,2,6,6,-tetramethyl-1-piperidinyloxy radical (TEMPO), sodium hypochlorite, and sodium bromide to provide useful cellouronic acids. The ox…
The addition of octylamine-modified poly(acrylic acid) to nanocrystal quantum dots (NQDs) results in robust, alcohol-soluble nanoparticles that can be readily incorporated into titania matrices without large changes in photoluminescence quantum yields. This approach relies on the amphiphilic nature of the polymer to c…
We describe a new family of discrete supramolecules comprising leucine-zipper peptides noncovalently assembled upon cognate leucine zippers fused to a dendrimer core. Circular dichroism and sedimentation equilibrium experiments clearly demonstrate that each leucine-zipper dendrimer (D-EZ4 or D-KZ4) can noncovalently d…
Arrays of highly ordered Zn(1-x)MnxS quantum wires with x ranging from 0.01 to 0.3 and with lateral dimensions of 3, 6, and 9 nm were synthesized within mesoporous SiO2 host structures of the MCM-41 and SBA-15 type. The hexagonal symmetry of these arrays (space group p6m) and the high degree of order was confirmed by…
The dynamics of the synthesis of a mesoporous silica material SBA-15 is followed using time-resolved in situ 1H NMR and transmission electron microscopy (TEM). Block copolymer-silica particles of two-dimensional hexagonal symmetry evolve from an initially micellar solution. The synthesis was carried out with the block…