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Material Suitable (material + suitable)

Distribution by Scientific Domains

Polymers and Materials Science	60%

Selected Abstracts

A Transparent, Flexible, Low-Temperature, and Solution-Processible Graphene Composite Electrode

ADVANCED FUNCTIONAL MATERIALS, Issue 17 2010
Haixin Chang
Abstract The synthesis and preparation of a new type of graphene composite material suitable for spin-coating into conductive, transparent, and flexible thin film electrodes in ambient conditions is reported here for the first time. Solution-processible graphene with diameter up to 50 ,m is synthesized by surfactant-assisted exfoliation of graphite oxide and in situ chemical reduction in a large quantity. Spin-coating the mixing solution of surfactant-functionalized graphene and PEDOT:PSS yields the graphene composite electrode (GCE) without the need for high temperature annealing, chemical vapor deposition, or any additional transfer-printing process. The conductivity and transparency of GCE are at the same level as those of an indium tin oxide (ITO) electrode. Importantly, it exhibits high stability (both mechanical and electrical) in bending tests of at least 1000 cycles. The performance of organic light-emitting diodes based on a GCE anode is comparable, if not superior, to that of OLEDs made with an ITO anode. [source]

A convenient and versatile hydroponic cultivation system for Arabidopsis thaliana

PHYSIOLOGIA PLANTARUM, Issue 3 2004
Hanna Norén
A versatile two-step cultivation procedure for Arabidopsis thaliana is described for the production of large quantities of leaf material suitable for biochemical and biophysical analysis. The first step comprises a miniature greenhouse made out of a plastic pipette box to grow the seedlings to the six-leaf stage. For continued growth, the seedlings are transferred to hydroponic cultivation using an opaque container covered by a styrofoam lid. Transfer of the small seedlings to hydroponic culture is facilitated by growth in separate pipette tips, which protects vulnerable roots from damage. The hydroponic cultivation system is easy to scale-up and produces large amounts of relatively large leaves and roots. This hydroponic system produces enough plant material to make Arabidopsis a feasible model for biochemical and biophysical experiments, which can be combined with the available genetic information to address various aspects of plant functional genomics. [source]

[Cr8(PhCO2)16O4]·4CH3CN·2H2O: structural origin of magnetic anisotropy in a molecular spin cluster

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2010
John Fielden
The Cr4O4 hetero-cubane-centered octachromium(III) cluster [Cr8(PhCO2)16O4] crystallizes from fluorobenzene,acetonitrile as dodeca-,2 -benzoato-tetrabenzoatotetra-,4 -oxido-octachromium(III) acetonitrile tetrasolvate dihydrate, [Cr8(C7H5O2)16O4]·4C2H3N·2H2O, (I). Crystals produced by this method are significantly more stable than the originally published dichloromethane pentasolvate, [Cr8(PhCO2)16O4]·5CH2Cl2 [Atkinson et al. (1999). Chem. Commun. pp. 285,286], leading to a significantly higher quality structure and allowing the production of large quantities of high-quality nondeuterated and deuterated material suitable for inelastic neutron scattering (INS) measurements. Compound (I) reveals a higher symmetry structure in which the cluster sits on a twofold rotation axis, and is based on an asymmetric unit containing four crystallographically independent Cr positions, two oxide ligands, eight benzoate ligands, two acetonitrile solvent molecules and one disordered water molecule. All the Cr atoms are six-coordinate, with an octahedral geometry for the inner cubane and a more highly distorted coordination environment in the outer positions. Despite the higher symmetry, the coordination geometries observed in (I) are largely similar to the dichloromethane pentasolvate structure, indicating that crystal-packing effects have little influence on the molecular structure of [Cr8(PhCO2)16O4]. Close structural analysis reveals that the high magnetic anisotropy observed in the INS measurements is a consequence of the distorted coordination geometry of the four outer Cr atoms. [source]

Silicone,Poly(hexylthiophene) Blends as Elastomers with Enhanced Electromechanical Transduction Properties,

ADVANCED FUNCTIONAL MATERIALS, Issue 2 2008
F. Carpi
Abstract Dielectric elastomers are progressively emerging as one of the best-performing classes of electroactive polymers for electromechanical transduction. They are used for actuation devices driven by the so-called Maxwell stress effect. At present, the need for high-driving electric fields limits the use of these transduction materials in some areas of potential application, especially in the case of biomedical disciplines. A reduction of the driving fields may be achieved with new elastomers offering intrinsically superior electromechanical properties. So far, most attempts in this direction have been focused on the development of composites between elastomer matrixes and high-permittivity ceramic fillers, yielding limited results. In this work, a different approach was adopted for increasing the electromechanical response of a common type of dielectric elastomer. The technique consisted in blending, rather than loading, the elastomer (poly(dimethylsiloxane)) with a highly polarizable conjugated polymer (undoped poly(3-hexylthiophene)). The resulting material was characterised by dielectric spectroscopy, scanning electron microscopy, tensile mechanical analysis, and electromechanical transduction tests. Very low percentages (1,6 wt %) of poly(3-hexylthiophene) yielded both an increase of the relative dielectric permittivity and an unexpected reduction of the tensile elastic modulus. Both these factors synergetically contributed to a remarkable increase of the electromechanical response, which reached a maximum at 1 wt % content of conjugated polymer. Estimations based on a simple linear model were compared with the experimental electromechanical data and a good agreement was found up to 1 wt %. This approach may lead to the development of new types of materials suitable for several types of applications requiring elastomers with improved electromechanical properties. [source]

Methacrylic Polymers Containing Optically Active Side-Chain Carbazole: Synthesis, Characterization and Photoconductive Properties

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 9 2008
Luigi Angiolini
Abstract Two novel optically active polymethacrylates bearing in the side chain a cyclic chiral group of one prevailing absolute configuration linked to the carbazole chromophore, deriving from the related monomers (S)-(,)-3-methacryloyloxy- N -[3-(9-ethylcarbazolyl)]pyrrolidine [(S)-(,)-MECP] and (S)-(+)-2-methacryloyloxy- N -[3-(9-ethylcarbazolyl)]succinimide [(S)-(+)-MECSI], have been prepared and characterized with the aim to obtain materials suitable to photoconductive applications. Poly[(S)-(,)-MECP] and poly[(S)-(+)-MECSI] exhibit remarkable thermal stability, with glass transition temperature around 200,°C and decomposition temperatures in the range 330,350,°C. Spectroscopic, thermal and chiroptical characterizations indicate the occurrence of dipolar interactions among the side chain moieties and the presence of chiral conformation at least for chain segments of the macromolecules. The photoconductive properties are discussed in terms of extent of conjugation in the side chain based on the electron-acceptor or electron-donator properties of the optically active ring linked to the carbazole group. [source]