Materials Literature
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A self-assembly layer-by-layer (LBL) technique was used for the sequential adsorption of polycation, poly(diallyldimethylammonium chloride) (PDDA) and polyanion, sulfonated polyaniline (SPANI) on glass, indium-tin-oxide (ITO) coated glass plates, polystyrene sulfonate (PSS)/glass and PSS/ITO surfaces, respectively. Th…
A coupling of size exclusion chromatography (SEC) and liquid chromatography at the critical adsorption point (LC CAP) has been applied to simultaneous discrimination of stereoregular poly(ethyl methacrylate)s (PEMAs) according to their molar mass and tacticity. The two-dimensional SEC/LC CAP separations were carried o…
Thin films of solvent-free molecule-based magnets [Cp*2Fe]•+[TCNE]•- and V(TCNE)x are grown by chemical vapor deposition on KBr pellets. [Cp*2Fe]•+[TCNE]•- films are crystalline and magnetically order at 3.7 K. Despite of their faceted grain morphology, V(TCNE)x films are amorphous. They exhibit field-dependent magnet…
Photoelectrochemical cells have been constructed by depositing monolayers of oriented covalently linked zinc/free base porphyrin heterodimers onto ∼30 nm nonporous layers of TiO 2 on ITO, deposited by metal−organic chemical vapor deposition (MO-CVD), and onto ∼100 nm porous, nanostructured TiO 2 layers, spin-coated fr…
The cure reactions of phenylethynyl end-capped polyimides were investigated using solid-state 13 C magic-angle spinning (MAS) nuclear magnetic resonance (NMR). A 13 C-labeled model compound ( 13 C-PEPA-3,4‘-ODA) and an imide oligomer ( 13 C-PETI-5) were synthesized and characterized. The thermal cure process for 13 C-…
The electrochemical and photophysical properties of a variety of neutral pi-associated [2]catenanes have been explored by using cyclic voltammetry, absorption and luminescence spectrophotometry and the measurement of exited-state lifetimes. Several trends that could be correlated with interactions between the mechanic…
Chemical oxidation of the linear tricobalt compound Co 3 (dpa) 4 Cl 2 ( 1 ) with 1 equiv of NOBF 4 yields the one-electron oxidized species [Co 3 (dpa) 4 Cl 2 ] + ( 1 + ), which crystallizes from dichloromethane as a solvate [Co 3 (dpa) 4 Cl 2 ][BF 4 ]·2CH 2 Cl 2 ( 2 ·2CH 2 Cl 2 ). The crystal structure of 2 · x CH 2…
The kinetic stability of the complex [Gd(DTPA)]2- (H5DTPA = diethylenetriamine-N,N,N',N",N"-pentaacetic acid), used as a contrast-enhancing agent in magnetic resonance imaging (MRI), is characterised by the rates of the exchange reactions that take place with the endogenous ions Cu2+ and Zn2+. The reactions predominan…
The rheological properties of different generations of hyperbranched polyesters in 1-methyl-2-pyrrolidinone solvent and their blends with a poly(2-hydroxyethyl methacrylate) are examined in this study. All the hyperbranched polyester solutions exhibit Newtonian behavior, with steady shear viscosities independent of sh…
The molecular arrangements of three different alkyl-substituted oligothiophenes both in two-dimensional adsorbed layers at a substrate interface and in bulk three-dimensional crystals were studied. Scanning tunneling microscopy (STM) was used to investigate the ordering of the conjugated oligomers in two-dimensional l…
Bimetallic gold and platinum particles of the Pt−Au and Au−Pt core−shell type are prepared using hydrogen reduction and radiolysis techniques. The optical absorption spectra are recorded and compared to various Au−Pt particles described in the literature. Au core Pt shell particles catalyze the hydrogen reduction of s…
Control over self-assembling polymers is characterized by size-exclusion chromatography: The polymer, formed from cobalt porphyrins functionalized with two pyridine ligands, organizes to a high molecular mass (>100 kDa) in solution (see scheme). The mean molecular mass can be precisely controlled by adding monofunctio…
Different relaxation rates of water protons are enhanced by a contrast agent for magnetic resonance imaging (MRI). A supramolecular adduct of poly-β-cyclodextrin and [(MnII(tpps)]4− is described. Oxidation of the manganese center to MnIII causes a marked decrease in the observed relaxivity r1p (see scheme), which make…
Isotactic (it-) and syndiotactic (st-) poly(methyl methacrylate)s (PMMAs) were synthesized by anionic polymerization in toluene at −78 °C with t -C 4 H 9 MgBr and t -C 4 H 9 Li/(C 2 H 5 ) 3 Al, respectively, as initiators. Polymers were assembled by the stepwise immersion of a 9-MHz quartz-crystal microbalance (QCM) a…
We describe the spontaneous self-assembly and the superstructure of a discrete surfactant-encapsulated cluster, (DODA) 40 (NH 4 ) 2 [(H 2 O) n ⊂Mo 132 O 372 (CH 3 COO) 30 (H 2 O) 72 ] ( 2, n ≈ 50), which consists of a hollow giant isopolyoxomolybdate core covered by a hydrophobic shell of dimethyldioctadecylammonium (…
Thermodynamically self-consistent integral equation theories (TC-IETs) supplemented by a one-phase freezing criterion, and Monte Carlo simulations, are used to investigate the thermodynamic and structural properties, as well as the phase diagram, of the hard-core Yukawa fluid (HCYF). The attention is focused on rapidl…
We present the first direct observation of temperature-dependent Fermi wave vectors in the quasi-one-dimensional conductor K 0.3 MoO 3 . By monitoring the position of these vectors through the Peierls transition using angle-resolved photoemission spectroscopy, we demonstrate that the temperature dependence of the char…
Although H 2 O has been the focus of a considerable amount of research since the beginning of the century, its peculiar physical properties are still not well understood. First we discuss some of the anomalies of this `complex fluid'. Then we describe a qualitative interpretation in terms of percolation concepts. Fina…
2 H NMR experiments in deuterated supercooled liquids are discussed in relation with α- and β-relaxation heterogeneity with particular emphasis on the latter. The results are exemplified using data from deuterated ortho -terphenyl, propylene carbonate and toluene where partial deuteration provides additional informati…
The magnetic and transport properties of layered manganese oxides La 1.2 Sr 1.8 Mn 2 - x T x O 7 (T = Fe, Co, Cr) are reported. The undoped oxide La 1.2 Sr 1.8 Mn 2 O 7 is ferromagnetic (FM) below 125 K where an insulating-metallic (I-M) transition occurs. Fe and Co doping have similar effects on the properties of La…