Search results for " Nanotube"
showing 10 items of 560 documents
α-Tocopherol-induced radical scavenging activity in carbon nanotubes for thermo-oxidation resistant ultra-high molecular weight polyethylene-based na…
2014
?-Tocopherol, a natural antioxidant molecule, was physically immobilized on the outer surface of multi-walled carbon nanotubes (CNTs), and the resulting functionalised particles (f-CNTs) were dispersed in ultra-high molecular weight polyethylene aiming at improving its thermo-oxidation resistance. The success of the functionalization was assessed through spectroscopic and thermal analysis, and the influence of the filler on the thermo-oxidative stability of the nanocomposites was investigated through rheological analyses and infrared spectroscopy. We found that the addition of only 1 wt.% of f-CNTs brings about a surprisingly high oxidation resistance, with a five/ten-fold increase of the i…
Halloysite nanotubes-based nanocomposites for the hydrophobization of hydraulic mortar
2021
Abstract The treatment of stone surfaces for their protection from ageing caused by natural and anthropogenic effects is an open issue in materials development for Cultural Heritage. We thought interesting to verify the suitability of a modified cellulose biofilm filled with halloysite nanotubes as wax compatibilizers to design a protecting layer. A hydraulic mortar was selected as a stone prototype. To improve the physico-chemical properties of the covering layer, wax microparticles have been incorporated to control transport, consolidation and wettability features. In particular, different application protocols have been studied, namely brushing and spraying, to assess whether the propos…
Effects of mechanical deformation on electronic transport through multiwall carbon nanotubes
2017
Abstract The effects of mechanical deformation on the electron transport behavior of carbon nanotubes (CNTs) are of primary interest due to the enormous potential of nanotubes in making electronic devices and nanoelectromechanical systems (NEMS). Moreover it could help to evaluate the presence of defects or to assess the type of CNTs that were produced. Conventional atomistic simulations have a high computational expense that limits the size of the CNTs that can be studied with this technique and a direct analysis of CNTs of the dimension used in nano-electronic devices seems prohibitive at the present. Here a novel approach was designed to realize orders-of-magnitude savings in computation…
Carbon nanotube field-effect devices with asymmetric electrode configuration by contact geometry
2014
We have studied experimentally the conductive properties of single walled carbon nanotube (SWNT) based field-effect type devices, with different contact geometries at the connecting electrode. The device designs are asymmetric with one end of the SWNT having the metal electrode deposited on top and immersing it, while at the other end, the SWNT is on top of the electrode. The devices were made with either gold or palladium as electrode materials, of which the latter resulted in different behavior of the different contact types. This is argued to be caused by the existence of a thin insulating layer of surface adsorbents on the palladium, possibly Pd5O4, the effect of which is enhanced by th…
A structural comparison of halloysite nanotubes of different origin by Small-Angle Neutron Scattering (SANS) and Electric Birefringence
2018
The structure of halloysite nanotubes (Hal) from different mines was investigated by Small-Angle Neutron Scattering (SANS) and Electric Birefringence (EBR) experiments. The analysis of the SANS curves allowed us to correlate the sizes and polydispersity and the specific surfaces (obtained by a Porod analysis of the SANS data) of the nanotubes with their specific geological setting. Contrast matching measurements were performed on patch Hal (from Western Australia) in order to determine their experimental scattering length density for a more precise analysis. Further characterization of the mesoscopic structure of Hal was carried out by Electric Birefringence (EBR), which allowed to study th…
Chapter 16 - Carbon Nanotubes: Synthesis, Characterization, and Applications in Drug-Delivery Systems
2019
International audience; Nanoparticles are increasingly being considered in the medical field as an effective means to deliver drugs of interest or as diagnostic biosensors. Carbon nanotubes (CNTs) are an allotropic form of carbon related to the fullerene family. Their exceptional thermal, mechanical, and electronical properties together with their tubular shape, offering a high surface area and enabling adsorption or conjugation of a wide variety of therapeutic drugs or diagnostic agents, make CNTs attractive platforms for the treatment of various diseases. This chapter reviews the emerging synthesis, characterization, and and discusses the perspectives and obstacles of these promising nano…
Theoretical study of the interaction between carbon nanotubes and carboplatin anticancer molecules
2015
International audience; Full DFT calculations were carried out to study the interactions between single-wall functionalized carbon-based metallic nanotubes (CNTs) and carboplatin anticancer drugs. The geometry of the CNT-carboplatin was optimized considering different molecular configurations on inner and outer surfaces of the nanotubes. Simulation results show that the most stable physisorption state for molecules is to be located inside the nanotubes in a parallel configuration. Furthermore{,} we demonstrated that the molecular physisorption was reinforced as soon as the number of encapsulated carboplatin molecules increased{,} leading to a favored state where the nanovector is filled by …
Nanovector formation by functionalization of TRAIL ligand on single-walled carbon nanotube: Experimental and theoretical evidences
2015
Équipe 104 : Nanomatériaux; International audience; The synthesis and the characterization of a novel nanovector based on oxidized single-walled carbon nanotubes (SWCNT) functionalized with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) via noncovalent 1-pyrenebutanoic acid N-hydrosuccinimid ester (PSE) is described. Experimental noncovalent functionalized SWCNT by PSE are compared to full DFT theoretical predictions. For this, several experimental techniques are gathered to prove the well functionalization of oxidized SWCNT by pi-pi stacking such as micro Raman and XPS spectroscopy analysis coupled to full-DFT calculations. Scanning transmission electron microscopy (STEM) …
Theoretical Simulations on Electric Properties of CNT-Me and GNR-Me Interconnects Using Effective Media Approach
2011
Abstract To overcome disadvantages of nowadays microtechnology, a further miniaturization of electronic devices, high integration level as well as increase of both operation frequencies and power density is required, including the use of adequate materials and innovative chip interconnects. Due to their unique physical properties, especially due to a ballistic (without losses) mechanism of conductivity, carbon nanotubes (CNTs) and graphene nanoribbons (GNRs) attract a permanently growing technological interest, for example, as promising candidates for nanointerconnects in a high-speed electronics.
Simulations on the mechanism of CNT bundle growth upon smooth and nanostructured Ni as well as θ-Al2O3 catalysts
2011
Abstract In the current study, we have performed ab initio DFT calculations on the gradually growing 2D periodic models of capped single-wall carbon nanotubes (SW CNTs) upon their perpendicular junctions with the Ni(111) substrate, in order to understand the peculiarities of the initial stage of their growth on either smooth or nanostructured catalytic particles. Appearance of the adsorbed carbon atoms upon the substrate follows from the dissociation of CVD hydrocarbon molecules, e.g., CH4: (CH4)ads → (CH)ads+3Hads and (CH)ads → Cads+Hads. (Since the effective growth of CNTs upon Ni nanoparticles occur inside the nanopores of amorphous alumina, we have also simulated analogous surface react…