Nes Ziona, Israel
Nes Ziona, Israel

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Hong S.Y.,University of Oxford | Kreizman R.,Weizmann Institute of Science | Rosentsveig R.,Weizmann Institute of Science | Zak A.,NanoMaterials Ltd. | And 6 more authors.
European Journal of Inorganic Chemistry | Year: 2010

Various inorganic salts can be encapsulated inside the comparatively narrow (0.8-2 nm) hollow core of single-walled carbon nanotubes (SWNTs) by molten phase capillary wetting. A new synthetic strategy is presented allowing the formation of one dimensional (1D) inorganic crystals or core- shell nanotubular structures by using multiwall WS2 nanotubes as host templates. Molten phase wetting with CsI results in the formation of 1D crystal structures inside WS2 nanocapillaries with a Moiré pattern. The relatively large diameter of the WS2 nanotube (with inner and outer diameters of ca. 10 and 20 nm, respectively), allows a conformal folding of the guest PbI2 layers (PbI2@WS2 core-shell nanotubes) on the interior wall of the WS2 nanotube-template, thusleading to relatively efect-free core-shell inorganic nanotubular structures, which have not been previously observed within carbon nanotubes (CNTs). Core-shell WS 2@MoS2 nanotubes can be obtained by the gas-phase reaction of MoCl5 with sulfur in the presence of WS2 nanotubes. The mechanism of imbibition/solidification of the molten salt into the hollow cores of MoS2 nanotubes has been studied by molecular dynamics simulations, showing major differences between layered compounds and those with quasi-isotropic structure. Theoretical considerations also show the conditions for the stability of such core-shell 1D nanostructures. These new strategies can open up many possibilities for the synthesis of new nanotubular structures. © 2010 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-IP | Phase: NMP-2008-1.2-1 | Award Amount: 12.34M | Year: 2009

The objective of the AddNano project is to investigate the prospects for overcoming the many existing technological barriers in the supply and usage chain, towards the establishment of a large scale market introduction of a new generation of fluid lubricants incorporating nanomaterials. The AddNano consortium combines technological expertise and industrial representation from all parts of the prospective value chain to investigate the development of new nano-based lubricants. Fluid lubricants are used in almost every field of human technological activity and their purpose is multifold: they reduce frictional resistance, protect the engine against wear between contacting surfaces, remove wear debris, reduce heating and contribute to cooling, improve fuel economy, improve emissions. Advanced nanomaterials recently developed, such as inorganic fullerene-like materials (IFs) and others, have shown some initial promise for their contribution to reducing friction and enhancing protection against wear. If able to be developed into full commercial-scale production, if they can be incorporated in a stable fashion into full formulations, and if their performance benefits relative to the best of conventional technologies can be sustained under those circumstances, they offer the prospect for some performance breakthroughs not seen since the development of the now ubiquitous anti-wear additives, Zinc Dialkyl Dithiophosphates (ZDDPs), around 70 years ago. Within engine oils and other lubricant applications, such as transmission fluids, and for greases used in rotational bearings, the potential exists for lubricants containing nanomaterials to significantly reduce friction and enhance machine durability. This can contribute to substantial energy savings, reduced equipment maintenance and longer machine lifetime.


Oila A.,Northumbria University | Sanderson L.,Northumbria University | Bull S.,Northumbria University | Fleischer N.,NanoMaterials Ltd.
Tribology - Materials, Surfaces and Interfaces | Year: 2010

The synthesis of inorganic fullerene-like materials (IFLMs) represents a major scientific breakthrough, and recently, new coatings and lubricants incorporating inorganic fullerene-like nanoparticles have been produced within the integrated European project FOREMOST. The objective of the work presented here was to assess the influence of IFLM in lubricants on the contact fatigue and wear performance of tribological contacts subjected to rolling/sliding motion such as gears. The wear tests were carried out using a double disc rig with specimens manufactured from S156 steel. The lubricants tested were two gear oils without IFLM and mixed with IFLM. The results show that a significant increase in the operational life of rolling/sliding components can be achieved using lubricants incorporating IFLMs. © 2010 W. S. Maney & Son Ltd.


Kreizman R.,Weizmann Institute of Science | Schwartz O.,Weizmann Institute of Science | Deutsch Z.,Weizmann Institute of Science | Itzhakov S.,Weizmann Institute of Science | And 4 more authors.
Physical Chemistry Chemical Physics | Year: 2012

A synthetic route for preparation of inorganic WS 2 nanotube (INT)-colloidal semiconductor quantum dot (QD) hybrid structures is developed, and transient carrier dynamics on these hybrids are studied via transient photoluminescence spectroscopy utilizing several different types of QDs. Measurements reveal efficient resonant energy transfer from the QDs to the INT upon photoexcitation, provided that the QD emission is at a higher energy than the INT direct gap. Charge transfer in the hybrid system, characterized using QDs with band gaps below the INT direct gap, is found to be absent. This is attributed to the presence of an organic barrier layer due to the relatively long-chain organic ligands of the QDs under study. This system, analogous to carbon nanotube-QD hybrids, holds potential for a variety of applications, including photovoltaics, luminescence tagging and optoelectronics. This journal is © the Owner Societies 2012.


Burghaus U.,North Dakota State University | Zak A.,NanoMaterials Ltd. | Rosentsveig R.,Weizmann Institute of Science
Israel Journal of Chemistry | Year: 2010

A simple ultra-high vacuum sample temperature ramping technique can be used to characterize the confinement effects and different adsorption sites on nanotube (NT) bundles deposited on a support such as silica. Results for inorganic NTs such as WS 2 and TiO 2 NTs are compared with data for carbon nanotubes and inorganic WS 2 fullerene-like nanoparticles. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Reddy C.S.,Technion - Israel Institute of Technology | Zak A.,Nano Materials Ltd. | Zussman E.,Technion - Israel Institute of Technology
Journal of Materials Chemistry | Year: 2011

Tungsten disulfide inorganic nanotubes (WS 2 INTs), which are available now in large amounts, were embedded into a poly methyl methacrylate (PMMA) nanofiber matrix. The PMMA solution and PMMA-WS 2 INT suspensions were electrospun to form aligned nanofiber meshes. TEM analysis revealed that WS 2 INTs are well dispersed within the PMMA fiber matrix and aligned along the fiber axes. Characteristic Raman signatures of WS 2 INTs were observed for the composite fiber meshes. The characteristic optical absorption band of WS 2 INTs shifted to the blue wavelength region in the presence of PMMA, a shift indicating a significant interaction between WS 2 INTs and PMMA. The thermal stability of WS 2 INT-embedded PMMA meshes was increased by 23 °C, in comparison to PMMA. The elastic modulus of PMMA fiber meshes was increased 10 times and 22 times, when WS 2 INTs were embedded and aligned along the fiber axes, for 1 wt% and 2 wt% respectively, and without compromising the tensile strength of the PMMA fiber mesh. Respective 35% and 30% increases in the tensile strength and toughness of the composite fibers were recorded. In addition, the dielectric constant of composite fiber meshes was 61% higher than that of PMMA fiber meshes. The developed PMMA-WS 2 INT organic-inorganic composites featuring enhanced stiffness and toughness may have potential applications as transparent high energy absorption materials. © 2011 The Royal Society of Chemistry.


Coppa N.V.,Nanomaterials Company | Milani A.M.,Nanomaterials Company | Fardig D.A.,Nanomaterials Company
41st International Conference on Environmental Systems 2011, ICES 2011 | Year: 2011

Drying of brine using physical processes such as spray-drying, evaporation and other physical methods have been shown to yield a thick paste rather than a dry solid powder. Paste formation is undesirable because it is difficult to manage. It was speculated the cause of paste formation was a result of the presence of one or more components that ordinarily were liquid at room temperature. We have investigated classes of nanopowders that allow drying processes such as spray-drying and evaporation to yield a dry, manageable solid when added to brine solutions at low levels. We found nanopowders having high specific surface area apparently adsorbed the liquid or liquid forming components thus allowing dry solids to form. We observed in some cases that the nano-drying agent upon mixing with the brine caused de-coloring. These and other observations described may have implications regarding the understanding of the effects of brine stabilizing agents such as sulfuric acid on brine-drying properties. In this paper we describe so-called nano-drying agents and their effects on drying. Generalizations derived from considering several drying agent types has led to the possibility of deriving drying agents from materials generated by current or proposed life support systems. © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.


Coppa N.V.,Nanomaterials Company | Milani A.M.,Nanomaterials Company | Fardig D.A.,Nanomaterials Company
41st International Conference on Environmental Systems 2011, ICES 2011 | Year: 2011

The phase composition of dried brine solids that is the nature of the solid materials present in brine has not been reported. The lack of this data is largely a result of producing crystalline dried brine solids without also causing preparative artifacts such as decomposition. Ordinarily, dried solids do not form when drying brine solids; rather, a thick paste forms having little or no crystalline constituents, thus making phase identification of the solids impossible. It is speculated the cause of paste formation was a result of the presence of one or more components that were liquid at room temperature. Dried brine solids were prepared using a spray drying process at 100 C and a nanopowder drying agent that sequestered certain brine components. The nanopowder drying agent was mixed with the brine prior to drying at a concentration that did not interfere with analysis using powder x-ray diffraction. Our results show that the brine solids are composed of solid solutions of sodium potassium sulfate, sodium/potassium phosphate, sodium chloride, sodium carbonate/bicarbonate urea and other minor phases. The dominant crystalline in all cases was a K2Na(SO4)2, the presence of which is most likely the result of brine stabilization with oxone, an oxidizing agent containing potassium peroxymonosulfate. In this paper, we provide experimental details of our preparative and analytical technique and detailed phase composition of dried brines. © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.


Zak A.,NanoMaterials Ltd. | Sallacan-Ecker L.,NanoMaterials Ltd. | Margolin A.,NanoMaterials Ltd. | Feldman Y.,Weizmann Institute of Science | And 4 more authors.
Fullerenes Nanotubes and Carbon Nanostructures | Year: 2011

The growth mechanism of WS2 nanotubes is briefly discussed. Two distinct growth mechanisms can be delineated, leading to somewhat different products: 1) thick (50-150 nm) and very long (20-50 microns and above) nanotubes consisting of many (> 20) layers, and 2) slender (20-25 nm) nanotubes with 5-10 layers. The synthesis of large amounts of pure WS2 nanotubes belonging to the first category in the large-scale fluidized-bed reactor is described. Characterization of the nanotubes, which grow catalyst-free by a number of analytical techniques, is reported. The nanotubes reveal highly crystalline order, suggesting very good mechanical behavior and numerous applications, especially in the field of nanocomposites. Copyright © Taylor & Francis Group, LLC.


Krause M.,Helmholtz Center Dresden | Krause M.,TU Dresden | Mucklich A.,Helmholtz Center Dresden | Zak A.,NanoMaterials Ltd. | And 2 more authors.
Physica Status Solidi (B) Basic Research | Year: 2011

Closed capped WS 2 nanotubes with diameters from 30 to 110 nm are studied by high resolution transmission electron microscopy (HRTEM). The tubes exhibit preferentially a hexagonal stacking order. Atomic resolution images of a 30 nm diameter tube reveal a zigzag chirality. A lattice expansion in c-axis direction of ≤11% is found within the outermost triple layers. The tube caps often display regular polygon angles. Structural defects like grain boundaries, nonplanar triple layers, dislocations, platelet-like fragments, terraces, and amorphous precipitates are identified. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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