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Fabrication Route (fabrication + route)
Selected AbstractsNovel Fabrication Route to Al2O3,TiN Nanocomposites Via Spark Plasma SinteringJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2006Lianjun Wang A novel method for the preparation of Al2O3,TiN nanocomposites was developed. A mixture of TiO2, AlN, and Ti powder was used as the starting material to synthesize the Al2O3,TiN nanocomposite under 60 MPa at 1400°C for 6 min using spark plasma sintering. X-ray diffractometry, scanning electron microscopy, and transmission electron microscopy were used for detailed microstructural analysis. Dense (up to 99%) nanostructured Al2O3,TiN composites were successfully fabricated, the average grain size being less than 400 nm. The fracture toughness (KIC) and bending strength (,b) of the nanostructured Al2O3,TiN composites reached 4.22±0.20 MPa·m1/2 and 746±28 MPa, respectively. [source] The Effect of Polymer Optoelectronic Properties on the Performance of Multilayer Hybrid Polymer/TiO2 Solar CellsADVANCED FUNCTIONAL MATERIALS, Issue 4 2005P. Ravirajan Abstract We report a study of the effects of polymer optoelectronic properties on the performance of photovoltaic devices consisting of nanocrystalline TiO2 and a conjugated polymer. Three different poly(2-methoxy-5-(2,-ethylhexoxy)-1,4-phenylenevinylene) (MEH-PPV)-based polymers and a fluorene,bithiophene copolymer are compared. We use photoluminescence quenching, time-of-flight mobility measurements, and optical spectroscopy to characterize the exciton-transport, charge-transport, and light-harvesting properties, respectively, of the polymers, and correlate these material properties with photovoltaic-device performance. We find that photocurrent is primarily limited by the photogeneration rate and by the quality of the interfaces, rather than by hole transport in the polymer. We have also studied the photovoltaic performance of these TiO2/polymer devices as a function of the fabrication route and device design. Including a dip-coating step before spin-coating the polymer leads to excellent polymer penetration into highly structured TiO2 networks, as was confirmed through transient optical measurements of the photoinduced charge-transfer yield and recombination kinetics. Device performance is further improved for all material combinations studied, by introducing a layer of poly(ethylene dioxythiophene) (PEDOT) doped with poly(styrene sulfonic acid) (PSS) under the top contact. Optimized devices incorporating the additional dip-coated and PEDOT:PSS layers produced a short-circuit current density of about 1,mA,cm,2, a fill factor of 0.50, and an open-circuit voltage of 0.86,V under simulated AM,1.5 illumination (100,mW,cm,2, 1,sun). The corresponding power conversion efficiency under 1,sun was ,,0.4,%. [source] Scalable Cylindrical Metallodielectric MetamaterialsADVANCED MATERIALS, Issue 38-39 2009Nicholas Gibbons A novel approach for fabricating metallodielectric metamaterials is reported through the exploitation of a floated roll technique. This process offers an efficient and scalable fabrication route for these multilayer structures, obviating the need for multiple depositions. These nanostructures can offer exciting new optical properties such as negative refraction and sub-wavelength imaging. [source] Solvent/non-solvent sintering: A novel route to create porous microsphere scaffolds for tissue regenerationJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2008Justin L. Brown Abstract Solvent/non-solvent sintering creates porous polymeric microsphere scaffolds suitable for tissue engineering purposes with control over the resulting porosity, average pore diameter, and mechanical properties. Five different biodegradable biocompatible polyphosphazenes exhibiting glass transition temperatures from ,8 to 41°C and poly (lactide- co -glycolide), (PLAGA) a degradable polymer used in a number of biomedical settings, were examined to study the versatility of the process and benchmark the process to heat sintering. Parameters such as: solvent/non-solvent sintering solution composition and submersion time effect the sintering process. PLAGA microsphere scaffolds fabricated with solvent/non-solvent sintering exhibited an interconnected porosity and pore size of 31.9% and 179.1 ,m, respectively which was analogous to that of conventional heat sintered PLAGA microsphere scaffolds. Biodegradable polyphosphazene microsphere scaffolds exhibited a maximum interconnected porosity of 37.6% and a maximum compressive modulus of 94.3 MPa. Solvent/non-solvent sintering is an effective strategy for sintering polymeric microspheres, with a broad spectrum of glass transition temperatures, under ambient conditions making it an excellent fabrication route for developing tissue engineering scaffolds and drug delivery vehicles. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] A novel fabrication route for auxetic polyethylene, part 2: Mechanical propertiesPOLYMER ENGINEERING & SCIENCE, Issue 7 2008R.S. Webber Auxetic ultra high molecular weight polyethylene (UHMWPE) has been fabricated by omitting the extrusion stage usually required to form the characteristic nodule-fibril microstructure of this material. This new route consists of compaction followed by multiple sintering treatments, with the best results using two successive sintering treatments. This article examines the mechanical properties of cylindrical compacts subjected to between one and four successive sintering treatments. The indentation resistance of the double-sintered material was found to be 2.5 times that of conventionally processed UHMWPE and similar to that found in the extruded form of auxetic polyethylene. The flexural strength and strain to failure increase dramatically with the first sintering treatment and then remain almost constant. This processing route has potential for the production of more complex, useful shapes than can currently be produced since it removes the limitations imposed by the geometry of the barrel required for the extrusion stage. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] | ||||||||||