Materials Literature
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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…
Differential scanning calorimetry (DSC) and magnetic measurements were performed to study the influence of ferromagnetic 3-d transition elements Fe and Co on structural and magnetic properties of ferromagnetic shape memory alloys Ni2MnGa. Addition of Fe or Co on the Ni sites decreases the temperature of martensitic ph…
Nanoscale diblock copolymer domains are aligned via top-down/bottom-up hierarchical assembly. Grating substrates template cylinder alignment with demonstrated 5000:1 aspect ratio for 100 μm domains extendable to arbitrary length scales. Depending on trough depth and amount of deposited polymer, aligned domains are (1)…
Poly(L-lysine)/hyaluronan (PLL/HA) films were chemically cross-linked with a water soluble carbodiimide (EDC) in combination with a N-hydroxysulfo-succinimide (NHS) to induce amide formation. Fourier transform infrared spectroscopy confirms the conversion of carboxylate and ammonium groups into amide bonds. Quartz cry…
The magnetic properties of Cu2Cl4(CH3CN)2 are reported. Initially reported by Rundle and Willett [J. Chem. Phys. 40, 838, (1964)], the title compound consists of dimeric Cu(II) ions doubly bridged by two chloride ions. Each Cu(II) ion is further bonded to an additional nonbridging chloride ion and a nonbridging aceton…
Recent experiments have demonstrated that the deviation of the single-particle displacement distribution from Gaussian form in a dense quasi-two-dimensional colloid suspension is a result of heterogenous dynamics that involves cooperative motions of neighboring colloid particles [J. Chem. Phys. 47, 9142 (2001)]. In th…
We discuss different aspects of the optical properties in a single CdTe spherical quantum dot after performing a systematic study of the eigenvalues, wave functions, and their dominant symmetries within the $8\ifmmode\times\else\texttimes\fi{}8$ $\mathbf{k}\ensuremath{\cdot}\mathbf{p}$ Kane-Weiler Hamiltonian derived…
Hydroxylation of proline residues in the Yaa position of the Gly-Xaa-Yaa repeated sequence to 4(R)-hydroxyproline is essential for the formation of the collagen triple helix. A small number of 3(S)-hydroxyproline residues are present in most collagens in the Xaa position. Neither the structural nor a biological role i…
New polymers having high solid-state fluorescence quantum yields and the ability to tune their electron affinity without effecting their band gap using hyperconjugative interactions is reported. The novel three-dimensional poly(phenylene vinylenes) having [2.2.2] bicyclic ring systems shown were synthesized, and the d…
We study different regimes in the dynamics of swelling of a long polymer chain from a compact globule. Depending on the age or degree of self-entanglement inside of the globule, we consider the limiting cases of “freshly formed” globule and “old” globule. Considering the density of polymer in a globule, which influenc…
Femtosecond laser pulse induced structural changes in silica glass and their role in changing the refractive index of the glass have been investigated using ab initio molecular dynamics simulation methods based on finite-temperature density functional theory. The average nearest-neighbor Si-O, Si-Si, and O-O distances…
[structure: see text] The multistep synthesis of a calixarene joined to a second calixarene via a long spacer is described. Since each calixarene bears multiple galactose-based units (known to bind strongly to rat hepatoma cells), there existed the possibility of cross-linking the cancer cells into a network. The comp…
The present contribution describes an unsophisticated yet highly efficient process to make dicarboxyl telechelic isotactic polypropylene containing pendant nitro groups via the oxidative degradation of commercially available crystalline polypropylene with nitric acid. The obtained crystalline polymer has a narrow mole…
Hydrolysis of native (amorphous) polyhydroxybutyrate (nPHB) granules isolated from different sources by soluble PHB depolymerase of Rhodospirillum rubrum in vitro requires the presence of a heat-stable compound (activator). The activator was purified and was resistant against various physical and chemical stresses suc…
We investigated the structures formed when blends of poly(styrene- b -ferrocenyl silane) (PS- b -FS) and poly(styrene- b -2-vinyl pyridine) (PS- b -P 2 VP) were spread at the air/water interface. The results demonstrated that new structures were formed which were distinct from those formed when either of the copolymer…
We report on the design, fabrication, and initial characterization of vertically aligned carbon nanofiber-based microfabricated field emission devices with an integrated out-of-plane electrostatic focusing electrode. The potential placed on this electrode was found to have a profound impact on the diameter of the beam…