Solvent-induced Morphology of the Binary Mixture of Diblock Copolymer in Thin Film: The Block Length and Composition Dependence of Morphology

A series of binary SB blend samples with various overall volume fraction of PS (Phi(PS)) and different discrete distribution of the block length (denoted as d(PS) or d(PB)) were prepared by mixing various asymmetric poly(styrene)-block-poly(butadiene) (SB) block copolymers with a symmetric SB block copolymer. The influences of the external solvent field, composition, and the block length distribution on the morphologies of the blends in the thin films were investigated by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The experimental results revealed that after solvent annealing, the interface of the blend thin films depended mainly on the cooperative effects of the annealing solvent and the inherently interfacial curvature of the blends. Upon exposure to the saturated vapor of cyclohexane, which has preferential affinity for the PB block, a "threshold" of Phi(PS) (approximate 0.635-0.707) was found. Below such threshold, the influence of the annealing solvent played an important role on the interfacial curvature of the blend thin film.

A novel sensitive solid-state electrochemiluminescence sensor material: Ru(bpy)(2+)(3) doped SiO2@MWNTs coaxial nanocable

A simple, large scale, and one-step process for the preparation of tris(2,2'-bipyridyl)ruthenium(I) (Ru(bpy)(3)(2+)) doped SiO2@carbon nanotubes (MVNTs) coaxial nanocable used for an ultrasensitive electrochemiluminescence (ECL) is presented for the first time. More importantly, a directly coated as-formed functional material on ITO electrode surface exhibits excellent ECL behavior, good stability, and high sensitivity in the presence of tripropylamine (TPA). This novel functional material will find potential applications in biosensor, electrophoresis and electroanalysis.

Bifunctional nanostructure of magnetic core luminescent shell and its application as solid-state electrochemiluminescence sensor material

Bifunctional nanoarchitecture has been developed by combining the magnetic iron oxide and the luminescent Ru(bpy)(3)(2+) encapsulated in silica. First, the iron oxide nanoparticles were synthesized and coated with silica, which was used to isolate the magnetic nanoparticles from the outer-shell encapsulated Ru(bpy)(3)(2+) to prevent luminescence quenching. Then onto this core an outer shell of silica containing encapsulated Ru(bpy)(3)(2+) was grown through the Stober method. Highly luminescent Ru(bpy)(3)(2+) serves as a luminescent marker, while magnetic Fe3O4 nanoparticles allow external manipulation by a magnetic field. Since Ru(bpy)(3)(2+) is a typical electrochemiluminescence (ECL) reagent and it could still maintain such property when encapsulated in the bifunctional nanoparticle, we explored the feasibility of applying the as-prepared nanostructure to fabricating an ECL sensor; such method is simple and effective. We applied the prepared ECL sensor not only to the typical Ru(bpy)(3)(2+) co-reactant tripropylamine (TPA), but also to the practically important polyamines. Consequently, the ECL sensor shows a wide linear range, high sensitivity, and good stability.

Organic photovoltaic cells using hexadecafluorophthalocyaninatocopper (F16CuPc) as electron acceptor material

We fabricated organic photovoltaic cells by using hexadecafluorophthalocyaninatocopper (F16CuPc) as electron acceptor material and para-sexiphenyl (p-6P) as electron donor material. F16CuPc has wide absorption spectrum from 550 nm to 850 nm, which covers the maximum of solar photo flux. The measurement of their external quantum efficiency (EQE) demonstrated that the photocurrent comes from the excitons created in F16CuPc, which were separated into free electrons and holes at heterojunction interface of p-6P and F16CuPc. Moreover, F(16)FuPc with excellent air-stability improved the environmental stability of photovoltaic cells, and the unencapsulated cells exhibited the shelf lifetime of exceeding a week.

Synthesis and characterization of soluble poly(amideimide)s bearing triethylamine sulfonate groups as gas dehumidification membrane material

A series of soluble poly(amide-imide)s (PAIs) bearing triethylammonium sulfonate groups were synthesized directly using trimellitic anhydride chloride (TMAC) polycondensation with sulfonated diamine such as 2,2'-benzidinedisulfonic acid (BDSA), 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid (ODADS), and nonsulfonated diamine 4,4-diaminodiphenyl methane in the presence of triethylamine. The resulting copolymers exhibited high molecular weights (high inherent viscosity), and a combination of desirable properties such as good solubility in dipolar aprotic solvents, film-forming capability, and good mechanical properties. Wide-angle X-ray diffraction revealed that the polymers were amorphous. These copolymers showed high permeability coefficients of water vapor because of the presence of the hydrophilic triethylammonium sulfonate groups. The water vapor permeability coefficients (P-w) and permselectivity coefficients of water vapor to nitrogen and methane [alpha(H2O/N-2) and (alpha(H2O/CH4)] Of the films increased with increasing the amount of the triethylammonium sulfonated groups.

Effect of the addition of YAG(Y3Al5O12) nanopowder on the mechanical properties of lanthanum zirconate

La2Zr2O7 (LZ) is a promising thermal barrier coating material for the high-temperature applications, which could be significantly toughened by the YAG nanopowder incorporated into the matrix. The composites of xYAG/(1-x)LZ (Y=10, 15, 20 vol. %, LZ-x-YAG) were densified by means of high-pressure sintering (HPS) under a pressure of 4.5 GPa at 1650 degrees C for 5 min, by which a high-relative density above 93% could be obtained. The morphologies of the fractured surfaces were investigated by the scanning electron microscope, and the fracture toughness and Vicker's-hardness of the composites were evaluated by the microindentation. The grain size of the LZ matrix drops significantly with the addition of YAG nanoparticles and the fracture type changes from the intergranular to a mixture type of the transgranular and intergranular in the nanocomposites. The LZ-20-YAG nanocomposite has a fracture toughness of 1.93 MPa m(1/2), which is obviously higher than that of the pure LZ (1.57 MPa m(1/2)), and the toughening mechanism is discussed in this paper.

Synthesis and properties of a novel isomeric polyimide/SiO2 hybrid material

A novel isomeric polyimide/SiO2 hybrid material was successfully prepared through sol-gel technique, and its structure, thermal properties and nano-indenter properties were investigated. First, 3-[(4-phenylethynyl)phthalimide]propyl triethoxysilane (PEIPTES) was successfully synthesized, its structure was characterized by elemental analysis, FT-IR and C-13 NMR. The researches on solubility and thermal properties of PEIPTES show that it can be used for modifying nano-SiO2 precursor. Nano-SiO2 precursor was synthesized by tetraethoxysilane (TECS) through sol-gel technique. Then the PEIPTES solution and the nano-SiO2 precursor were mixed for 6 h to let the PEIPTES molecules react with the nano-SiO2 precursor, and modified nano-SiO2 precursor was obtained. The modified reaction was confirmed by the analyses of FT-IR. At last, isomeric polyimide/SiO2 hybrid material was produced by using isomeric polyimide resin solution and the modified nano-SiO2 precursor after heat treatment process. The structure analysis by SEM indicated that SiO2 particles dispersed in isomeric polyimide matrix homogeneously with nanoscale. Thermogravimetric analyzer, dynamic mechanical thermal analyzer and nano-indenter XP was employed to detect the properties of the materials, the results demonstrated that isomeric polyimide/SiO2 hybrid material has much better thermal properties and nano-indenter properties than those of isomeric polyimide.

Enhanced response induced by polyelectrolyte-functionalized ionic liquid in glucose biosensor based on sol-gel organic-inorganic hybrid material

In this work, a polyelectrolyte-functionalized ionic liquid (PFIL) was firstly incorporated into a sol-gel organic-inorganic hybrid material (PFIL/sol-gel). This new composite material was used to immobilize glucose oxidase on a glassy carbon electrode. An enhanced current response towards glucose was obtained, relative to a control case without PFIL. In addition, chronoamperometry showed that electroactive mediators diffused at a rate 10 times higher in the apparent diffusion coefficient in PFIL-containing matrices. These findings suggest a potential application in bioelectroanalytical chemistry.

High-pressure sintering study of a novel hard material (W0.5Al0.5)C-0.5 without binder metal

A novel hard material of (W0.5Al0.5)C-0.5 has been successfully sintered under high-pressure (4.5 GPa). The influence of sintering time and temperature on the microstructure, Vickers microhardness and density of the as-prepared specimens are well described. Interestingly, sintering temperature has an amazing influence on the hardness, density and microstructure of the specimen while the sintering time does not. It is found that the most suitable sintering condition from our work is 1600 degrees C and 10 min under pressure of 4.5 GPa. The hardness and relative density of the as-prepared sample can reach 2340 kg mm(-2) and 98.62%, respectively. The cell parameters of the sintered specimen is found to be little smaller than that of the powder, which we propose is related to the high pressure.

Negative differential resistance and memory effect in diodes based on 1,4-dibenzyl C60 and zinc phthalocyanine doped polystyrene hybrid material

Negative differential resistance (NDR) and memory effect were observed in diodes based on 1,4-dibenzyl C60 (DBC) and zinc phthalocyanine doped polystyrene hybrid material. Certain negative starting sweeping voltages led to a reproducible NDR, making the hybrid material a promising candidate in memory devices. It was found that the introduction of DBC enhanced the ON/OFF current ratio and significantly improved the memory stability. The ON/OFF current ratio was up to 2 orders of magnitude. The write-read-erase-reread cycles were more than 10(6), and the retention time reached 10 000 s without current degradation.

Crystallization of mechanically alloyed amorphous W-Mg alloy under high pressure

Pure metal powder mixtures of W and Mg at the desired composition were milled in conventional high-energy ball mill, and amorphous alloy W50Mg50 was obtained after milling for 20 h. The structure evolution of elemental powder mixtures was studied following milling and subsequent high pressure and high temperature treatment. The amorphous alloy transform into a nanocrystalline material below 1050 degreesC at 4.0 GPa. On increasing the temperature, it transforms into a mixture of several new crystal phases under high-pressure condition. It also found that both mechanical alloying and high pressure treatment are the two necessary processes to form the nanocrystalline and the new phases.