Home About us Contact
|
Home About us Contact | ||
|
|
||
Inorganic Materials (inorganic + material)
Selected AbstractsUnprecedented "One-Finger-Push"-Induced Phase Transition With a Drastic Color Change in an Inorganic Material,ADVANCED MATERIALS, Issue 21 2007M. Gaudon A drastic color transition from green to brownish-red in the CuMo1,xWxO4 system occurs during a first-order phase transition. This study shows that it is possible to control this transition in terms of temperature or pressure with respect to the tungsten content (see figure). Hence, the use of these compounds for new applications as temperature indicators or shock detectors is feasible. [source] Hybrid Bioorganic,Inorganic Materials Prepared by Site-Specific Ligation of Peptides to Functionalized Polydisperse Silica ParticlesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 12 2005Pascal Joly Abstract We describe the synthesis of semicarbazide- or glyoxylyl-functionalized polydisperse silica particles and their use for the preparation of hybrid polypeptide,silica materials. The peptides were attached to the surface of functionalized silicas by site-specific ,-oxo hydrazone or semicarbazone ligation. The reaction of semicarbazide silicas with a model glyoxylyl peptide was found to be very efficient under stoichiometric conditions and led to ligation yields of about 90,%. The use of glyoxylyl silicas and of hydrazinoacetyl peptides led to lower yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Nonvolatile Memory Concepts Based on Resistive Switching in Inorganic MaterialsADVANCED ENGINEERING MATERIALS, Issue 4 2009Thomas Mikolajick Abstract Solid state memories play an important role for the electronic systems used in today's information society. The classical approach of charge storage is expected to reach its physical scaling limits very soon. New storage effects are therefore receiving significant interest from industry and academia. In the paper we summarize recent results on resistive switching effects in inorganic materials obtained in the research groups of the authors. We discuss the implications of these results for the suitability of the investigated material systems as well as for the direction of further research. [source] Functional Chromium Wheel-Based Hybrid Organic,Inorganic Materials for Dielectric ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 20 2009Vito Di Noto Abstract The first example of organic,inorganic hybrid materials based on the embedding of a chromium,nickel wheel cluster {[(n-C3H7)2NH2]- [Cr7NiF8(O2C4H5)16]} (Cr7Ni) into poly(methyl methacrylate) (PMMA) and the characterization of the dielectric properties of the obtained material is described. By an optimized copolymerization of the methacrylate-functionalized chromium,nickel wheel with methyl methacrylate in a cluster/monomer 1:200 molar mixture, a homogeneous hybrid material CrNi_MMA200 is obtained. The electrical responses of the non-doped PMMA and of the hybrid material were studied by broadband dielectric spectroscopy (BDS) from 0.01,Hz to 10,MHz and over the temperature range of 5,115,°C. The permittivity profiles reveal two relaxation peaks in the materials, which correspond to the , and , relaxation modes of the PMMA matrix. The position of these modes shifts toward higher frequencies as temperature increases. BDS is a powerful tool revealing the intimate miscibility of the various components of the hybrid material, thus indicating that, on a molecular scale, the material proposed is a homogeneous system. Finally, a value of the dielectric constant of 2.9 at 25,°C and 1,kHz is determined. This value is noticeably lower than the value of 3.2 obtained for pristine PMMA prepared following the same synthesis protocol. Thus, these results classify the hybrid CrNi_MMA200 as an appealing starting material for the development of dielectric polymeric layers for the development of innovative capacitors, transistors, and other microelectronic devices. The vibrational properties of the hybrid materials are investigated by Fourier-transform infrared (FT-IR) and Raman spectroscopy, whereas the thermal behavior is analyzed by thermogravimetric analysis (TGA). Swelling experiments are used to qualitatively evaluate the crosslinking density of the hybrid materials. The integrity of the wheels once embedded in the macromolecular backbone is confirmed by extended X-ray absorption fine structure (EXAFS) and electron spin resonance (EPR) spectroscopic measurements. [source] Stretchable, Curvilinear Electronics Based on Inorganic MaterialsADVANCED MATERIALS, Issue 19 2010Dae-Hyeong Kim Abstract All commercial forms of electronic/optoelectronic technologies use planar, rigid substrates. Device possibilities that exploit bio-inspired designs or require intimate integration with the human body demand curvilinear shapes and/or elastic responses to large strain deformations. This article reviews progress in research designed to accomplish these outcomes with established, high-performance inorganic electronic materials and modest modifications to conventional, planar processing techniques. We outline the most well developed strategies and illustrate their use in demonstrator devices that exploit unique combinations of shape, mechanical properties and electronic performance. We conclude with an outlook on the challenges and opportunities for this emerging area of materials science and engineering. [source] Inorganic Materials and Ionic Liquids: Large-scale Nanopatterning of Single Proteins used as Carriers of Magnetic Nanoparticles (Adv. Mater.ADVANCED MATERIALS, Issue 5 20105/2010) Ricardo Garcia, Eugenio Coronado, and co-workers demonstrate on p. 588 large-scale patterning of single ferritin molecules by sequential (atomic force microscopy local oxidation) and parallel approaches (lithographically controlled wetting). The nanopattern size matches the size of the protein (,10 nm). Electrostatic interactions, capillary forces, surface functionalization, and nanolithography are used to achieve the desired protein organization. [source] Preparation of Inorganic Materials Using Ionic LiquidsADVANCED MATERIALS, Issue 2 2010Zhen Ma Abstract Conventional synthesis of inorganic materials relies heavily on water and organic solvents. Alternatively, the synthesis of inorganic materials using, or in the presence of, ionic liquids represents a burgeoning direction in materials chemistry. Use of ionic liquids in solvent extraction and organic catalysis has been extensively studied, but their use in inorganic synthesis has just begun. Ionic liquids are a family of non-conventional molten salts that can act as templates and precursors to inorganic materials, as well as solvents. They offer many advantages, such as negligible vapor pressures, wide liquidus ranges, good thermal stability, tunable solubility for both organic and inorganic molecules, and much synthetic flexibility. In this Review, the use of ionic liquids in the preparation of several categories of inorganic and hybrid materials (i.e., metal structures, non-metal elements, silicas, organosilicas, metal oxides, metal chalcogenides, metal salts, open-framework structures, ionic liquid-functionalized materials, and supported ionic liquids) is summarized. The status quo of the research field is assessed, and some future perspectives are furnished. [source] Topography Mediated Patterning of Inorganic Materials by Spray Pyrolysis,ADVANCED MATERIALS, Issue 22 2006D. Beckel Microstructured ceramic thin films are produced by spray pyrolysis of metal salt solutions onto micromachined substrates. The ceramic structures built on the substrate result from preferential assembly of particles on the edge of the initially micromachined structures, leading to smaller lateral dimensions (1,2 ,m in width) than the initial structures on the substrate (see figure). The assembly process amplifies the height of the initial structures by a factor of approximately thirty, resulting in features with an aspect ratio of three. [source] Fabrication and evaluation of complementary logic circuits using zinc oxide and pentacene thin film transistorELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 9 2009Hiroyuki Iechi Abstract We fabricated hybrid complementary inverters with n-channel zinc oxide (ZnO) transistors as the n-type inorganic material and p-channel organic transistors using pentacene as the p-type organic material. The complementary inverter exhibited a large voltage gain of 10 to 12 and a cutoff frequency of 0.5 kHz. ZnO thin film transistors show n-type semiconducting properties having field-effect mobility of 2.1×10,3 cm2/Vs. On the other hand, pentacene thin film transistors show p-type semiconducting properties having field-effect mobility of 3.2×10,2 cm2/Vs. We describe basic charge transfer characteristics of ZnO thin films. The results obtained here demonstrate that it is important for the transistor using ZnO to be injected charge from electrode to semiconducting material effectively. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(9): 36,42, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10085 [source] Silica-Based, Organically Modified Host Material for Waveguide Structuring by Two-Photon-Induced PhotopolymerizationADVANCED FUNCTIONAL MATERIALS, Issue 5 2010Stefan Krivec Abstract The three-dimensional fabrication of optical waveguides has gained increasing interest in recent years to establish interconnections between electrical components on a very small scale where copper circuits encounter severe limitations. In this work the application of optically clear, organically modified porous silica monoliths and thin films as a host material for polymeric waveguides to be inscribed into the solid host structure by two-photon-induced photopolymerization is investigated. Porosity is generated using a lyotropic liquid crystalline surfactant/solvent system as a template for the solid silica material obtained by a sol,gel transition of a liquid precursor. In order to reduce the brittleness of the purely inorganic material, organic,inorganic co-precursor molecules that contain poly(ethylene glycol) chains are synthesized and added to the mixture, which successfully suppresses macroscopic cracking and leads to flexible thin films. The structure of the thus-obtained porous organic,inorganic hybrid material is investigated by atomic force microscopy. It is shown that the modified material is suitable for infiltration with photocurable monomers and functional polymeric waveguides can be inscribed by selective two-photon-induced photopolymerization. [source] The smear layer in endodontics , a reviewINTERNATIONAL ENDODONTIC JOURNAL, Issue 1 2010D. R. Violich Abstract Root canal instrumentation produces a layer of organic and inorganic material called the smear layer that may also contain bacteria and their by-products. It can prevent the penetration of intracanal medicaments into dentinal tubules and influence the adaptation of filling materials to canal walls. This article provides an overview of the smear layer, focusing on its relevance to endodontics. The PubMed database was used initially; the reference list for smear layer featured 1277 articles, and for both smear layer dentine and smear layer root canal revealed 1455 publications. Smear layer endodontics disclosed 408 papers. A forward search was undertaken on selected articles and using some author names. Potentially relevant material was also sought in contemporary endodontic texts, whilst older books revealed historic information and primary research not found electronically, such that this paper does not represent a ,classical' review. Data obtained suggests that smear layer removal should enhance canal disinfection. Current methods of smear removal include chemical, ultrasonic and laser techniques , none of which are totally effective throughout the length of all canals or are universally accepted. If smear is to be removed, the method of choice seems to be the alternate use of ethylenediaminetetraacetic acid and sodium hypochlorite solutions. Conflict remains regarding the removal of the smear layer before filling root canals, with investigations required to determine the role of the smear layer in the outcomes of root canal treatment. [source] Celite-mediated linking of polyurethane block copolymers and the impact on the shape memory effectJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Yong-Chan Chung Abstract Celite, a porous inorganic material with enormous surface area and hydroxyl groups on the surface, was used as a cross-linker of polyurethane (PU) copolymer chains to improve its shape memory and mechanical properties. PU copolymers with different Celite contents were prepared and characterized by IR, DSC, and universal testing machine. The glass transition temperature of PU copolymers was maintained around 20°C independent of Celite content. The shape memory and mechanical properties were dependent on when Celite was added during the polymerization reaction. The reaction in which Celite was added at the middle stage of polymerization showed the best shape memory and mechanical properties. The best shape recovery of PU was found at 0.3 wt % Celite and increased to 97% even after the third cycle. Likewise, the shape retention also maintained a remarkable 86% after three cycles. The reasons underlining the high shape recovery and shape retention by adopting Celite as a cross-linker are discussed in this article. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Generation of core/shell iron oxide magnetic nanoparticles with polystyrene brushes by atom transfer radical polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2007I. Garcia Abstract The functionalization of nanoparticle surfaces is required to improve the dispersion of an inorganic material inside an organic matrix. In this work, polystyrene (PS) brushes were grown on the surface of iron oxide magnetic nanoparticles with atom transfer radical polymerization and a grafting-from approach. After polymerization, the magnetic nanoparticles had a graft density of 0.9 PS chains/nm2. A sacrificial initiator was used to obtain a satisfactory result for the control of the polymerization, as its addition had to generate a sufficient concentration of persistent radicals (deactivator). A variety of techniques, such as Fourier transform infrared spectroscopy, thermogravimetric analysis, gel permeation chromatography, water contact-angle measurements, and atomic force microscopy, were used to characterize the nanoparticles. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4744,4750, 2007 [source] Frontal polymerization of acrylic monomers for the consolidation of stonePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 4 2005Silvia Vicini Abstract Polymeric products are largely used for consolidation of stone in the field of cultural heritage. Nevertheless, the main problem of polymeric compounds is related to their macromolecular nature, it being difficult for a polymer to penetrate inside the pores which may have a very small diameter. These considerations are the starting points for in situ polymerization. According to this technique, not the pre-formed polymer, but the monomer is introduced into the stone and it is polymerized in situ in a subsequent step. Frontal polymerization (FP) is a particular technique in which the heat released by the exothermal reaction of monomer to polymer conversion is exploited to promote the formation of a hot traveling front able to propagate and self-sustain the reaction. In the present work, FP is performed inside the pores of the stone and the results lead to the conclusion that the hot front is still active in the presence of an inorganic material which dissipates partially the heat released during the polymerization. In addition some recent applications of FP are discussed in comparison with the traditional polymerization for the in situ consolidation and protection of stones. Copyright © 2005 John Wiley & Sons, Ltd. [source] Inorganic Analogues of GrapheneEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 27 2010C. N. R. Rao Abstract The discovery of graphene has aroused great interest in the properties and phenomena exhibited by two-dimensional inorganic materials, especially when they comprise only a single, two or a few layers. Graphene-like MoS2 and WS2 have been prepared by chemical methods, and the materials have been characterized by electron microscopy, atomic force microscopy (AFM) and other methods. Boron nitride analogues of graphene have been obtained by a simple chemical procedure starting with boric acid and urea and have been characterized by various techniques that include surface area measurements. A new layered material with the composition BCN possessing a few layers and a large surface area discovered recently exhibits a large uptake of CO2. [source] Hybrid 2D and 3D Frameworks Based on ,-Keggin Polyoxometallates: Experiment and SimulationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 15 2005Anne Dolbecq Abstract The ,-Keggin polyoxomolybdate {,-PMoV8MoVI4O40,x(OH)xM4} is a versatile building unit, with M being either a ZnII or a LaIII capping ion located at the vertices of a slightly distorted tetrahedron. The charge of the Keggin unit depends on the number of protonated oxo bridging ligands, which has been shown to vary from 0 to 5. The Keggin entity can thus be either an anion (M = Zn, x = 0) or a cation (M = La, x = 3,5). The Zn derivative has been generated in situ by hydrothermal synthesis and forms a 2D material built from the connection of the cations by 4,4'-bipyridine ligands linked to the capping ZnII ions. The reaction of the chloride salt of the La derivative with di-, tri- and tetrasubstituted benzenecarboxylate ligands has allowed us to isolate 2D and 3D materials. The 3D materials seem to be the first examples of hybrid open frameworks based on Keggin building blocks. The 3D framework built from the connection of ,-Keggin units by trimesate ions exhibits tunnels filled only by water molecules, which can be partly removed and reintroduced at room temperature. Besides these experimental results, simulation has allowed us to generate two virtual hybrid structures derived from those of known silicates by replacing the Si ions by hypothetical ,-Keggin cations and the O -bridging ligands by terephthalate ions, thus showing that 3D frameworks with large pores can be envisioned in the chemistry of hybrid organic,inorganic materials based on ,-Keggin units and motivating further experimental investigations. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Synthesis and Physicochemical Characterization of meso -Functionalized Corroles: Precursors of Organic,Inorganic Hybrid MaterialsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2005Jean-Michel Barbe Abstract Cobalt(III) corroles exhibit an infinite selectivity for the coordination of carbon monoxide towards dioxygen and dinitrogen. This peculiar property thus allows their use as sensing devices for CO detection. Here are described the syntheses and physico-chemical characterization of meso mono-, bis- and tris(triethoxysilyl)-functionalized corroles, precursors of organic,inorganic materials. The corrole ring formation was achieved in every case using the "2+1" method involving the reaction of two equivalents of an encumbered dipyrromethane with one equivalent of an aromatic aldehyde in the presence of a catalytic amount of trifluoroacetic acid. The functionalization of the corrole by triethoxysilyl chains was carried out by a condensation reaction of an isocyanate, bearing a triethoxysilyl termination, either on an amino or hydroxy group. Each final compound and intermediate were characterized by various physico-chemical techniques such as 1H NMR, UV/Vis, MALDI/TOF or EI mass spectrometry and elemental analysis. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Nonvolatile Memory Concepts Based on Resistive Switching in Inorganic MaterialsADVANCED ENGINEERING MATERIALS, Issue 4 2009Thomas Mikolajick Abstract Solid state memories play an important role for the electronic systems used in today's information society. The classical approach of charge storage is expected to reach its physical scaling limits very soon. New storage effects are therefore receiving significant interest from industry and academia. In the paper we summarize recent results on resistive switching effects in inorganic materials obtained in the research groups of the authors. We discuss the implications of these results for the suitability of the investigated material systems as well as for the direction of further research. [source] Conjugated-Polymer-Based Lateral Heterostructures Defined by High-Resolution PhotolithographyADVANCED FUNCTIONAL MATERIALS, Issue 17 2010Jui-Fen Chang Abstract Solution processing of polymer semiconductors provides a new paradigm for large-area electronics manufacturing on flexible substrates, but it also severely restricts the realization of interesting advanced device architectures, such as lateral heterostructures with defined interfaces, which are easily accessible with inorganic materials using photolithography. This is because polymer semiconductors degrade, swell, or dissolve during conventional photoresist processing. Here a versatile, high-resolution photolithographic method is demonstrated for patterning of polymer semiconductors and exemplify this with high-performance p-type and n-type field-effect transistors (FETs) in both bottom- and top-gate architectures, as well as ambipolar light-emitting field-effect transistors (LEFETs), in which the recombination zone can be pinned at a photolithographically defined lateral heterojunction between two semiconducting polymers. The technique therefore enables the realization of a broad range of novel device architectures while retaining optimum materials performance. [source] Mussel-Inspired Polydopamine Coating as a Universal Route to Hydroxyapatite CrystallizationADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Jungki Ryu Abstract Bone tissue is a complex biocomposite material with a variety of organic (e.g., proteins, cells) and inorganic (e.g., hydroxyapatite crystals) components hierarchically organized with nano/microscale precision. Based on the understanding of such hierarchical organization of bone tissue and its unique mechanical properties, efforts are being made to mimic these organic,inorganic hybrid biocomposites. A key factor for the successful designing of complex, hybrid biomaterials is the facilitation and control of adhesion at the interfaces, as many current synthetic biomaterials are inert, lacking interfacial bioactivity. In this regard, researchers have focused on controlling the interface by surface modifications, but the development of a simple, unified way to biofunctionalize diverse organic and inorganic materials remains a critical challenge. Here, a universal biomineralization route, called polydopamine-assisted hydroxyapatite formation (pHAF), that can be applied to virtually any type and morphology of scaffold materials is demonstrated. Inspired by the adhesion mechanism of mussels, the pHAF method can readily integrate hydroxyapatites on ceramics, noble metals, semiconductors, and synthetic polymers, irrespective of their size and morphology (e.g., porosity and shape). Surface-anchored catecholamine moieties in polydopamine enriches the interface with calcium ions, facilitating the formation of hydroxyapatite crystals that are aligned to the c -axes, parallel to the polydopamine layer as observed in natural hydroxyapatites in mineralized tissues. This universal surface biomineralization can be an innovative foundation for future tissue engineering. [source] Surface Modification of Exfoliated Layered Gadolinium Hydroxide for the Development of Multimodal Contrast Agents for MRI and Fluorescence ImagingADVANCED FUNCTIONAL MATERIALS, Issue 21 2009Young-su Yoon Abstract A novel method for modifying the surface of magnetic-resonance-contrasting layered gadolinium hydroxide (LGdH) is developed providing them with water- and bio-compatibility and acid-resistance, all of which are essential for medical applications. A stable colloid of exfoliated layers is synthesized by exchanging interlayer anions of LGdH with oleate ions. The delaminated layers are successively coated with phospholipids with poly(ethylene glycol) tail groups, and their effectiveness as a contrast agent for magnetic resonance imaging (MRI) is demonstrated. The adaptability of this surface modification approach for incorporating functional molecules and fabricating a fluorescent colloid of LGdH, which has the potential utility as a multimodal probe, is also demonstrated. This result provides a novel approach for expanding the applications of layered inorganic materials and developing a new class of MRI contrast agents. [source] 1D and 3D Ionic Liquid,Aluminum Hydroxide Hybrids Prepared via an Ionothermal Process,ADVANCED FUNCTIONAL MATERIALS, Issue 14 2007S. Park Abstract Room-temperature ionic liquids (RTILs) are used as hierarchically multifunctional components by employing them not only as templates and co-solvents for fabricating nanostructured materials but also proton conductors for electrochemical devices. RTIL/aluminum hydroxide (RTIL,Al) hybrids containing various nanometer-sized shapes, including 1D nanorods with hexagonal tips, straight and curved nanofibers, nanofibers embedded in a porous network, and 3D octahedral-, polyhedral-, and angular spherical shapes are synthesized via a one-pot ionothermal process. The structures or shapes of the RTIL,Al hybrids are related to the anionic moieties, alkyl chain length of the RTILs, and the humidity during fabrication. In particular, the introduction of water molecules into the interface led to 3D isotropic growth of the hybrids by influencing intermolecular interactions between the RTILs and the building blocks. The shapes of the nanohybrids fabricated from RTILs containing short alkyl chains were dependent on the types of anions and on the level of humidity. These results indicate that the cooperative interactions between RTILs and aluminum hydroxides induces emerging shape-controlled hybrids. The shape-controlled nanohybrids show enhanced electrochemical properties compared to those of a conventional hybrid prepared by mixing RTILs and aluminum hydroxides, exhibiting tenfold or higher proton conductivity under anhydrous condition and thermal stability as a result of the continuous proton conduction channel and the one-pot-assembled nanoconfinement. This method is expected to be a useful technique for controlling the diverse shapes of nanometer-sized crystalline inorganic materials for a variety of applications, such as fuel cells, solar cells, rechargeable batteries, and biosensors. [source] Preparation of Inorganic Materials Using Ionic LiquidsADVANCED MATERIALS, Issue 2 2010Zhen Ma Abstract Conventional synthesis of inorganic materials relies heavily on water and organic solvents. Alternatively, the synthesis of inorganic materials using, or in the presence of, ionic liquids represents a burgeoning direction in materials chemistry. Use of ionic liquids in solvent extraction and organic catalysis has been extensively studied, but their use in inorganic synthesis has just begun. Ionic liquids are a family of non-conventional molten salts that can act as templates and precursors to inorganic materials, as well as solvents. They offer many advantages, such as negligible vapor pressures, wide liquidus ranges, good thermal stability, tunable solubility for both organic and inorganic molecules, and much synthetic flexibility. In this Review, the use of ionic liquids in the preparation of several categories of inorganic and hybrid materials (i.e., metal structures, non-metal elements, silicas, organosilicas, metal oxides, metal chalcogenides, metal salts, open-framework structures, ionic liquid-functionalized materials, and supported ionic liquids) is summarized. The status quo of the research field is assessed, and some future perspectives are furnished. [source] Synthesis of Inorganic NanotubesADVANCED MATERIALS, Issue 42 2009C. N. R. Rao Abstract Nanotubes constitute an exciting class of one-dimensional nanomaterials of which carbon nanotubes are recognized widely as materials of importance. The possibility of having inorganic nanotubes was recognized early in the 1990s, accompanied by the report of nanotubes of MoS2 and WS2. Since then, nanotubes of several inorganic materials have been prepared and characterized. While nanotubes of metal chalcogenides and oxides form a high proportion of the inorganic nanotubes investigated hither to, nanotubes of many other materials have also been prepared and characterized. Several synthetic strategies including both physical and chemical methods have been employed, of which the use of templates, precursors, and hydro- or solvothermal methods are prominent. In this article, we shall present a brief account of the present status of the synthesis of nanotubes of elemental materials as well as binary and complex metal oxides, chalcogenides, pnictides and carbides. [source] Self-Assembly: Molecular Self-Assembled Monolayers and Multilayers for Organic and Unconventional Inorganic Thin-Film Transistor Applications (Adv. Mater.ADVANCED MATERIALS, Issue 14-15 200915/2009) A self-assembled monolayer (SAM) of azo stillbazolium sandwiched between two conductive electrodes is shown. The upper and lower electrodes are doped silicon and a Hg drop, respectively, a configuration often used for measuring the conductivity of SAMs and multilayers of hybrid organic and inorganic materials. The evaluation and implementation of these unconventional materials in complex device architectures is highlighted in the review on page 1407 by Sara DiBenedetto et al. [source] Biologically Programmed Synthesis of Bimetallic Nanostructures,ADVANCED MATERIALS, Issue 15 2006M. Slocik Catalytic bimetallic nanoparticles are synthesized by exploiting the interaction between peptides and inorganic materials to program the peptide sequence such that it can serve as a template in the synthesis of gold nanoparticles as well as direct the binding to Pd ions to the surface of the Au nanoparticles (see figure). [source] Porous epoxies by reaction induced phase separation of removable alcohols: Control of spheroidal pore size by mass fraction, cure temperature, and reaction rate,JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Robert J. Klein Abstract Porous organic and inorganic materials with both random and controlled microstructures have utility in a variety of fields including catalysis, sensors, separations, optical platforms, tissue engineering, hydrogen storage, micro-electronics, medical diagnostics, as well as other applications. This work highlights a simple and general technique for tuning the pore size in crosslinking polymeric systems by adding a solvent poragen that phase separates during the curing process (reaction induced phase separation). The pore size can be controlled over large length scales ranging from microns to well below 100 nanometers. In this system an amine cured epoxy resin was reacted in the presence of the sacrificial poragen octadecanol, which is removed by vacuum-assisted evaporation once the epoxy components have reacted to form a solid, porous matrix. The importance of the present approach is based on the simplicity of the chemical formulation, the ease by which other epoxide or amine chemistries may be substituted for the two reactive components, and the control of pore size down to the nanometer scale by the addition of a small amount of catalyst. © 2010 Wiley Periodicals, Inc., J Appl Polym Sci, 2010 [source] Hydrodynamic behaviour of a full-scale anaerobic contact reactor using residence time distribution techniqueJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2009Isabel Capela Abstract BACKGROUND: The knowledge of the fluid pattern of full-scale anaerobic reactors is of fundamental importance for the optimisation of biological processes. High solids concentrations often lead to inefficient mixing conditions, which may reduce treatment capacity due to heterogeneity within the biomass. RESULTS: The hydrodynamic characteristics of a full-scale anaerobic contact reactor treating evaporator condensate from a sulphite pulp mill were investigated. The methodology applied was based on the residence time distribution (RTD) technique using lithium as a tracer. Different non-ideal hydraulic flow models were tested and the best model fitting RTD data was the Gamma distribution model with by-pass. It was concluded that the full-scale bioreactor presents a good degree of mixing with about 22% of non-effective volume due to the presence of high amounts of inorganic materials. CONCLUSION: As a result of this study it was possible to both improve the full-scale bioreactor performance and decrease the running costs by changes in the plant operation strategies which allowed reduction of the huge amount of inorganic materials contributing to the non-effective volume. The methodology is simple and results from a unique RTD experiment and confirms the importance of considering mixing characteristics when assessing complex full-scale treatment processes. Copyright © 2009 Society of Chemical Industry [source] Two- and three-dimensional multinuclear stray-field imaging of rotating samples with magic-angle spinning (STRAFI-MAS): From bio to inorganic materialsJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2010Alan Wong PhD Abstract Purpose: To revisit and illustrate the potential of a simple and effective multidimensional stray-field imaging technique with magic-angle spinning, known as STRAFI-MAS. Materials and Methods: STRAFI-MAS images are acquired with a standard NMR magnet and a traditional magic-angle sample spinning (MAS) probe. The stray-field gradients are achieved by placing the MAS probe, along the z -direction, at a distance from the center of the magnet. No pulsed-field gradients are applied. The multidimensional spatial encoding is carried out by synchronizing the radiofrequency pulses with the sample MAS rotation. Results: Two-dimensional (2D) and 3D multinuclear images of various phantoms, including a tibia bone and silicon carbide, are recorded. Images of inorganic solids containing quadrupolar nuclei, 23Na and 27Al, are also explored for the first time by STRAFI-MAS. Conclusion: We have demonstrated that STRAFI-MAS is a simple and user-friendly technique for multidimensional imaging without the need of imaging equipment. With the current advancements in NMR and MRI methodologies, STRAFI-MAS is expected to be further developed and improved. We anticipate that STRAFI-MAS can spark a wide spectrum of interest, from material to bio science, where can benefit from high-resolution images. J. Magn. Reson. Imaging 2010;32:418,423. © 2010 Wiley-Liss, Inc. [source] Biodoped Ceramics: Synthesis, Properties, and ApplicationsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2006Smita Y. Gadre This feature article focuses on biodoped ceramics. These are inorganic materials in which biological materials are incorporated, thus adding new functionality to them. A brief overview of the prominent synthesis techniques for biodoped ceramics, with emphasis on modified sol,gel processes for metal oxide matrices, is given first. Theoretical treatments of the encapsulation of biologicals within a porous ceramic matrix are reviewed. Experimental studies of the stability and dynamics of protein entrapment in silica and other ceramic matrices are also discussed. Finally, key applications of biodoped ceramics in biochemical species detection, bio-catalysis, and drug delivery are presented. [source] | ||||||||||||||||||||||||||||||||||