Controlled polymerizations with constrained geometries
This short review focuses on recent advances in controlled polymerization and macromolecular architectonics by means of a variety of organized media with constrained geometries.
Materials Literature
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Acid–base surface free energies of solids and the definition of scales in the Good–van Oss–Chaudhury theory
The overwhelming basicity of all analysed surfaces strongly dependent on the choice of liquid triplet used for contact angle measurements and the negative values sometimes obtained for the square roots of the acid-base parameters can be summarized as the main problems arising from the application of the Good-van Oss-C…
Bioinspired phospholipid polymer biomaterials for making high performance artificial organs
Novel polymer biomaterials, which can be used in contact with blood, are prepared with strong inspiration from the surface structure of biomembrane. That is, the polymers with a phospholipid polar group in the side chain, 2-methacrylooyloxyethyl phosphorylcholine (MPC) polymers were synthesized. The MPC polymers can i…
Spin tunneling and phonon-assisted relaxation inMn12-acetate
We present a comprehensive theory of the magnetization relaxation in a ${\mathrm{Mn}}_{12}$-acetate crystal in the high-temperature regime $(T\ensuremath{\gtrsim}1 \mathrm{K}),$ which is based on phonon-assisted spin tunneling induced by quartic magnetic anisotropy and weak transverse magnetic fields. The overall rela…
Synthesis of highly ordered mesoporous silica materials using sodium silicate and amphiphilic block copolymers
A commercially important synthetic approach to highly ordered mesoporous silica materials (SBA-family) with 2-D hexagonal (P6mm), 3-D hexagonal (P63/mmc) and cubic (Im3m and Pm3m) structures, using sodium silicate as the silica source and amphiphilic block copolymers as the structure-directing agents is demonstrated.
Panoscopic materials: synthesis over ‘all’ length scales
For the latter half of the ‘Solid State 20th Century’ materials science has been the engine that propelled technology. As we enter the ‘Materials 21st Century’ it is abundantly clear that the insatiable demand for new materials for emerging technologies is driving materials synthesis and change. Materials chemistry wi…
The cytotoxicity of corrosion products of nitinol stent wire on cultured smooth muscle cells
Although nitinol is one of most popular materials of intravascular stents, there are still few confirmative biocompatibility data available, especially in vascular smooth muscle cells. In this report, the nitinol wires were corroded in Dulbecco's modified Eagle's medium with constant electrochemical breakdown voltage…
Optical spectroscopy of nanocrystalline cubic Y2O3:Er3+ obtained by combustion synthesis
We report the emission and upconversion spectra and the lifetimes of Er3+ doped Y2O3 nanocrystalline and bulk samples. We found that when the nanocrystal and bulk samples of Y1.80Er0.20O3 were excited at 815 nm, the overall emission intensity was stronger for the bulk sample. However, the relative intensity of the (2H…
Highly fluorescent and electroactive molecular squares containing perylene bisimide ligands
Large functional molecular squares have been assembled with ditopic perylene bisimide bridging ligands and Pt(II) and Pd(II) phosphine corner units and their optical, electrochemical and spectroelectrochemical properties have been studied.
Multiscaling in inelastic collisions
We study relaxation properties of two-body collisions on the mean-field level. We show that this process exhibits multiscaling asymptotic behavior as the underlying distribution is characterized by an infinite set of nontrivial exponents. These nonequilibrium relaxation characteristics are found to be closely related…
Dendrimers as fluorescent sensors with signal amplification
In a fourth generation poly(propylene amine) dendrimer decorated with 32 dansyl units at the periphery and containing 30 aliphatic amine units in the interior, the strong fluorescence of all the dansyl units is quenched when a Co2+ ion is incorporated into the dendrimer.
Thermal and fire studies on polystyrene-clay nanocomposites
Nanocomposites of polystyrene and several organophilic clays have been prepared by a bulk polymerization technique. The resulting polymers have an intercalated structure and show enhanced thermal stability, as measured by thermogravimetric analysis and cone calorimetry, relative to virgin polystyrene, even when as lit…
Effect of surface treatment and sterilization processes on the corrosion behavior of NiTi shape memory alloy
Nickel-titanium (NiTi) alloy derives its biocompatibility and good corrosion resistance from a homogeneous oxide layer mainly composed of TiO(2), with a very low concentration of nickel. In this article, we described the corrosion behavior of NiTi alloys after mechanical polishing, electropolishing, and sterilization…
Evolution of vibrational excitations in glassy systems
The equations of the mode-coupling theory (MCT) for ideal liquid-glass transitions are used for a discussion of the evolution of the density-fluctuation spectra of glass-forming systems for frequencies within the dynamical window between the band of high-frequency motion and the band of low-frequency-structural-relaxa…
Towards nanostructured arrays of single molecule magnets: new Fe19 oxyhydroxide clusters displaying high ground state spins and hysteresis †
Ligands of general formula N(CHRCH2OH)(CH2CO2H)2 have been used to capture portions of the Fe(OH)2+ lattice to give particles containing up to nineteen magnetically coupled iron(III) centres. If R = Me or Et, lattices containing only Fe19 clusters result and single crystal X-ray diffraction shows that these are arrang…
Functionalized oligoarylenes as building blocks for new organic materials
Some of the current directions in research on new organic materials based on functionalized oligoarylenes are reviewed. Particular emphasis is placed upon the use of chemical synthesis for the incorporation of suitable functionalized oligoarylenes into more complex molecular and polymeric systems. Selected examples of…
Luminescence of nanocrystalline ZnSe:Mn2+
The luminescence properties of nanocrystalline ZnSe:Mn2+ prepared ia an inorganic chemical synthesis are described. Photoluminescence spectra show distinct ZnSe and Mn2+ related emissions, both of which are excited ia the ZnSe host lattice. The Mn2+ emission wavelength and the associated luminescence decay time depend…
Synthesis of single-walled carbon nanotube–Co–MgO composite powders and extraction of the nanotubes
A carbon nanotube–Co–MgO composite powder is prepared by reducing a Mg0.9Co0.1O solid solution in H2–CH4 atmosphere. The oxide matrix and part of the Co catalyst are dissolved by acid treatment without damage to the nanotubes. More than 80% of the carbon nanotubes have either one or two walls. The diameters of the nan…
Morphology and rheology of polystyrene nanocomposites based upon organoclay
A correlation between morphology development and rheology of polystyrene nanocomposites based upon organophilic layered silicates (organoclay) such as fluoromicas was found as a function of the silicate modification. Organoclay was obtained by means of ion exchange of clay with protonated amine-terminated polystyrenes…
BETS as a source of molecular magnetic superconductors (BETS = bis(ethylenedithio)tetraselenafulvalene)
BETS-based salts (BETS = bis(ethylenedithio)tetraselenafulvalene) incorporating Fe3+ ions are most interesting candidate systems for the observation of interplay of conductivity and magnetism. Indeed, in λ-(BETS)2FeCl4, conduction electrons in the BETS layers do interact with spins localised on the (FeCl4)− anions. Sy…