Search results for " alloy"
showing 10 items of 1757 documents
Covalently attached polymer mono- and multilayers on silanized glass substrates
1996
Abstract Applying grazing incidence FTIR and ellipsometry, the reaction of poly [(1-methyl-vinyl isocyanate)-alt-(maleic anhydride)](IAP) with amino-silanized glass and silicon oxide surfaces has been investigated. A reactive surface containing isocyanate and anhydride groups was formed after the adsorption of the polymer. The layer could be further functionalized using 2-aminoethanol. Multilayers could be built up by adsorbing a second layer of IAP onto an already reacted first layer of IAP.
Formation of nanorods by self-assembly of alkyl-substituted polyphenylene dendrimers on graphite
2000
Alkyl-substituted polyphenylene dendrimers with a tetrahedral or disk-like shape form self-assembled monolayers on graphite (HOPG) which show complex supramolecular structures, such as parallel rods of 6 nm diameter or two-dimensional crystals.
Polyisoprene-carbon black nanocomposites as tensile strain and pressure sensor materials
2004
Abstract Electrically conductive polymer composites (ECPC) are shown as prospective large-size flexible pressure and stretch sensors for detecting of dangerous deformations and vibrations of vehicle parts. Reversible change of resistance dependent on stretch and pressure is obtained in electro-conductive polymer nanocomposites. At certain concentrations of carbon nano-particles a change of electrical resistance by more than four orders is observed at 40% relative stretch. The maximum sensitivity of nanocomposites is observed in the vicinity of the transition of electro-conductive percolation. Nanocomposites exhibit a very weak semiconductor-like temperature dependence of resistance. The ten…
Second harmonic generation in self-assembled alternating multilayers of hemicyanine containing polymers and polyvinylamine
1995
Abstract Assembly of noncentrosymmetric multilayers is a facile technique for preparing noncentrosymmetric films avoiding electrical poling procedures and problems from subsequent relaxation of the induced orientational order. A maximum Xzzz of 13 × 10−9 esu was achieved for the assembly of up to six layers. Current problems are the long-term hydrolysation of the hemicyanine nonlinear optical chromophores and the reduction of polar orientation with increasing layer thickness.
Composites of ethylene-vinyl acetate copolymers with modified magnesium hydroxide-thermo-oxidative ageing
2014
Flame retardant composites must perform their protective roles permanently, also under conditions of intermittent or long-term exposure to sunlight, moisture or increased temperature. The aim of our work was characterization of the thermo-oxidative ageing (90 °C) and the changes in flammability of ethylene-vinyl acetate copolymer composites with 40 and 60 wt.% of magnesium hydroxide. The neat polymer and its composites were investigated for their thermal (DSC) and structural (FTIR) characteristics as well as their density, melt flow index, tensile properties and combustibility during ageing test. As FTIR results identified the different carbonyl groups in copolymer were created, the highest…
Mixed polymeric monolayers and Langmuir-Blodgett multilayers with functional low molecular weight guest compounds
2008
Abstract Mixed monolayers and Langmuir-Blodgett multilayers of functional low molecular weight guest compounds, especially nonlinear optical (NLO) dyes, within the matrix of an amphotropic spacer polymer have been prepared. The polymer matrix enabled the transfer of guest compounds not capable of self-organizing at the air-water interface by themselves. The structure of the LB multilayers and the transfer process were studied by small angle X-ray scattering and UV-visible spectroscopy. Good NLO coefficients were found in the mixed films.
Supramolecular isomerism in spin crossover networks with aurophilic interactions
2004
Assembly of FeII, 3-cyanopyridine and [Au(CN)2]– affords, in one-pot reaction, three coordination polymers that represent a genuine example of supramolecular isomerism with strong influence in the spin crossover regime of the FeII ions. Real Cabezos, Jose Antonio, Jose.A.Real@uv.es
Efficient photovoltaic and electroluminescent perovskite devices.
2015
Planar diode structures employing hybrid organic–inorganic methylammonium lead iodide perovskites lead to multifunctional devices exhibiting both a high photovoltaic efficiency and good electroluminescence. The electroluminescence strongly improves at higher current density applied using a pulsed driving method.
Thermo- and light responsive micellation of azobenzene containing block copolymers
2010
In this communication, the synthesis and characterization of thermo- and light responsive block copolymers is reported. PEO-b-PNIPAM polymers with azobenzene moieties were prepared and analyzed by turbidimetry, fluorescence, NMR and DLS measurements. A temperature controlled reversible formation as well as a light induced disruption and reformation of micellar structures in water was found.
Superexchange pathways in oxovanadium(IV) phosphates
1992
Abstract Oxovanadium(IV) phosphates show a diversity of magnetic behaviours that cannot be deduced from their respective structural features only. In part, this is due to the involvement of phosphate bridges in the spin transfer between V(IV) centres, and 31P solid state nuclear magnetic resonance becomes a key tool in determining the exchange mechanisms. The magnetic properties of a wide set of vanadium(IV) containing derivatives can be explained by realizing that a good overlap of the magnetic orbits may be achieved through paths involving phosphorus d orbitals.