Query: inorganic nanotubes

title: An overview of the recent advances in inorganic nanotubes.
abstract: Advanced nanomaterials play a prominent role in nanoscience and nanotechnology developments, opening new frontiers in these areas. Among these nanomaterials, due to their unique characteristics and enhanced chemical and physical properties, inorganic nanotubes have been considered one of the most interesting nanostructures. In recent years, important progress has been achieved in the production and study of these nanomaterials, including boron nitride, transition metal dichalcogenide nanotubular structures, misfit based nanotubes and other hybrid/doped nanotubular objects. This review is devoted to the in depth analysis of recent studies on the synthesis, atomic structures, properties and applications of inorganic nanotubes and related nanostructures. Particular attention is paid to the growth mechanism of these nanomaterials. This is a crucial point for the challenges ahead related to the mass production of high quality defect free nanotubes for a variety of applications.

title: Structural resolution of inorganic nanotubes with complex stoichiometry
abstract: Determination of the atomic structure of inorganic single walled nanotubes with complex stoichiometry remains elusive due to the too many atomic coordinates to be fitted with respect to X ray diffractograms inherently exhibiting rather broad features. Here we introduce a methodology to reduce the number of fitted variables and enable resolution of the atomic structure for inorganic nanotubes with complex stoichiometry. We apply it to recently synthesized methylated aluminosilicate and aluminogermanate imogolite nanotubes of nominal composition (OH)3Al2O3Si(Ge)CH3. Fitting of X ray scattering diagrams, supported by Density Functional Theory simulations, reveals an unexpected rolling mode for these systems. The transferability of the approach opens up for improved understanding of structure property relationships of inorganic nanotubes to the benefit of fundamental and applicative research in these systems.Structural determination of inorganic nanotubes has lagged far behind that of their carbon based counterparts. Here, the authors present a transferable methodology, combining wide angle X ray scattering and computation, to quantitatively resolve the atomic structure of inorganic nanotubes with complex stoichiometry.

title: Inorganic Nanotubes and Fullerene like Nanoparticles at the Crossroads between Solid State Chemistry and Nanotechnology.
abstract: Inorganic nanotubes (NTs) and fullerene like nanoparticles (NPs) of WS2 were discovered some 25 years ago and are produced now on a commercial scale for various applications. This Perspective provides a brief description of recent progress in this scientific discipline. The conceptual evolution leading to the discovery of these NTs and NPs is briefly discussed. Subsequently, recent progress in the synthesis of such NPs from a variety of inorganic compounds with layered (2D) structure is described. In particular, we discuss the synthesis of NTs from chalcogenide and oxide based ternary misfit layered compounds, as well as their structure and different growth mechanisms. Next we deliberate on the mechanical, optical, electrical, and electromechanical properties, which delineate them from their bulk counterparts and also from their graphene like analogues. Here, different experiments with individual NTs coupled with first principles and molecular dynamics calculations demonstrate the unique physical nature of these quasi 1D nanostructures. Finally, the various applications of the fullerene like NPs of WS2 and NTs formed therefrom are deliberated. Foremost among the possibilities are their extensive uses as superior solid lubricants. Combined with their nontoxicity and their facile dispersion, these NTs, with an ultimate strength of about 20 GPa, are likely to find numerous applications in reinforcing polymers, adhesives, textiles, medical devices, metallic alloys, and even concrete. Other potential applications in energy harvesting and catalysis are discussed in brief.

title: Torsional Resonators Based on Inorganic Nanotubes.
abstract: We study for the first time the resonant torsional behaviors of inorganic nanotubes, specifically tungsten disulfide (WS2) and boron nitride (BN) nanotubes, and compare them to that of carbon nanotubes. We have found WS2 nanotubes to have the highest quality factor (Q) and torsional resonance frequency, followed by BN nanotubes and carbon nanotubes. Dynamic and static torsional spring constants of the various nanotubes were found to be different, especially in the case of WS2, possibly due to a velocity dependent intershell friction. These results indicate that inorganic nanotubes are promising building blocks for high Q nanoelectromechanical systems (NEMS)

title: An assembly of organic inorganic composites using halloysite clay nanotubes
abstract: Halloysite is natural tubular clay suitable as a component of biocompatible nanosystems with specific functionalities. The selective modification of halloysite inner/outer surfaces can be achieved by exploiting supramolecular and covalent interactions resulting in controlled colloidal stability adjusted to the solvent polarity. The functionalized halloysite nanotubes can be employed as reinforcing filler for polymers as well as carriers for the sustained release of active molecules, such as antioxidants, flame retardants, corrosion inhibitors, biocides and drugs. The tubular morphology makes halloysite a perspective template for core shell metal supports for mesoporous catalysts. The catalysts can be incorporated with selective and unselective metal binding on the nanotubes' outer surface or in the inner lumens. Micropatterns of self assembled nanotubes have been realized by the droplet casting method. The selective modification of halloysite has been exploited to increase the nanotubes' ordering in the produced patterns. Pickering emulsions, induced by the self assembly of halloysite nanotubes on oil water interface, can be used for petroleum spill bioremediation and catalysis.

title: Polymer blend nanocomposites based on poly(L lactic acid) polypropylene and WS2 inorganic nanotubes
abstract: Tungsten disulphide inorganic nanotubes (INT WS2) have been incorporated into poly(L lactic acid) (PLLA)/polypropylene (PP) blends compatibilized with polypropylene grafted maleic anhydride (PP g MAH) and their effects on the morphology, thermal and mechanical properties of the resulting nanocomposites have been investigated. The nanofillers were uniformly dispersed at the nanoscale via a melt blending process. The addition of 1.0 wt% INT WS2 to the PLLA/PP blends hardly affected their thermal stability or their degradation mechanism. Differential scanning calorimetry (DSC) thermograms revealed the nucleating role of INT WS2 on both polymeric components, reflected not only in an increase in the crystallization temperature from the melt but also in a rise in the crystallization enthalpy and the suppression of the cold crystallization process; this effect was found to be more pronounced on PLLA and the blends rich in this component. Dynamic mechanical analysis (DMA) measurements demonstrated that the storage modulus of the nanocomposites was higher than those of the binary blends in the whole temperature range studied, ascribed to a synergistic effect of their increased crystallinity and the high INT WS2 rigidity. This study opens up new perspectives to develop novel INT WS2/polymer blend hybrid nanocomposites that show great potential for biomedical applications.

title: WS2 inorganic nanotubes reinforced poly(L lactic acid)/hydroxyapatite hybrid composite biomaterials
abstract: The present work reports on the incorporation of tungsten disulphide inorganic nanotubes (INT WS2) into poly(L lactic acid)/hydroxyapatite (PLLA/HA) and their effects on the processability, morphology, biocompatibility, thermal, tribological and mechanical properties of the resulting nanocomposites. Binary PLLA/HA and ternary PLLA/HA/INT WS2 composites were successfully prepared using a conventional melt blending technique. Morphological analysis indicates that the incorporation of INT WS2 into PLLA/HA improves the dispersibility of the HA microparticles and reduces their mean size, resulting in a larger interfacial area. Additionally, INT WS2 can act as efficient nucleating agents as well as reinforcing fillers in PLLA/HA blends, thus remarkably enhancing their chemical and thermal stability, mechanical performance under dry and SBF conditions as well as tribological properties. The improvements are more pronounced in the hybrid nanocomposite with the highest HA content, likely due to a synergistic effect of both micro and nano fillers on the matrix performance. Considering the good biocompatibility of the developed materials, the inexpensive synthetic process and the extraordinary properties of environmentally friendly INT WS2, this work may open up opportunities to produce new biopolymer/hydroxyapatite hybrid nanocomposites that are of great interest in bone tissue engineering applications.

title: Halloysite Nanotubes: Green Nanomaterial for Functional Organic Inorganic Nanohybrids.
abstract: The unique one dimensional nanoporous structure and the reactive external and internal surfaces make halloysite nanotube (HNT) an interesting nanomaterial for various applications. HNT is a green nanomaterial because it is easily available from abundant deposits in nature and is biocompatible with low cytotoxicity. After a brief introduction on the structure of HNT, recent advances in surface modification of HNT and its functional organic inorganic nanohybrids including hybrid nanocontainers, flame retardant nanocomposites, dye removal adsorbents, liquid marbles, and superamphiphobic coatings are introduced.

title: Biocompatibility of tungsten disulfide inorganic nanotubes and fullerene like nanoparticles with salivary gland cells.
abstract: Impaired salivary gland (SG) function leading to oral diseases is relatively common with no adequate solution. Previously, tissue engineering of SG had been proposed to overcome this morbidity, however, not yet clinically available. Multiwall inorganic (tungsten disulfide [WS2] nanotubes (INT WS2) and fullerene like nanoparticles (IF WS2) have many potential medical applications. A yet unexplored venue application is their interaction with SG, and therefore, our aim was to test the biocompatibility of INT/IF WS2 with the A5 and rat submandibular cells (RSC) SG cells. The cells were cultured and subjected after 1 day to different concentrations of INT WS2 and were compared to control groups. Growth curves, trypan blue viability test, and carboxyfluorescein succinimidyl ester (CFSE) proliferation assay were obtained. Furthermore, cells morphology and interaction with the nanoparticles were observed by light microscopy, scanning electron microscopy and transmission electron microscopy (TEM) and energy dispersive X ray spectroscopy. The results showed no significant differences in growth curves, proliferation kinetics, and viability between the groups compared. Moreover, no alterations were observed in the cell morphology. Interestingly, TEM images indicated that the nanoparticles are uptaken by the cells and accumulate in cytoplasmic vesicles. These results suggest promising future medical applications for these nanoparticles.

title: Thermoplastic Polymer Nanocomposites Based on Inorganic Fullerene like Nanoparticles and Inorganic Nanotubes
abstract: Using inorganic fullerene like (IF) nanoparticles and inorganic nanotubes (INT) in organic inorganic hybrid composite, materials provide the potential for improving thermal, mechanical, and tribological properties of conventional composites. The processing of such high performance hybrid thermoplastic polymer nanocomposites is achieved via melt blending without the aid of any modifier or compatibilizing agent. The incorporation of small quantities (0.1 4 wt. of IF/INTs (tungsten disulfide, IF WS2 or molybdenum disulfide, MoS2) generates notable performance enhancements through reinforcement effects and excellent lubricating ability in comparison with promising carbon nanotubes or other inorganic nanoscale fillers. It was shown that these IF/INT nanocomposites can provide an effective balance between performance, cost effectiveness, and processability, which is of significant importance for extending the practical applications of diverse hierarchical thermoplastic based composites.