Ref HAL: hal-01909394_v1
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Bridged silsesquioxane nanomaterials exhibit original mechanical properties thanks to the association of non-covalent and covalent interactions. Thanks to in situ high pressure spectroscopic studies, achieved in diamond anvil cells, the mechanical behavior of these materials was followed as a function of pressure. Figure 1: Schematic representation of bottom-up structuring in organic-inorganic hybrid silica through self-assembling process Vibrational studies on organic models coupled to ab-initio simulations show that H bond response to pressure is strengthening. In hybrid materials the H bond shows its ability to absorb the mechanical constrains by the modulation of H bond interactions. We thus show that the rigidity yielded by the inorganic polymerization is counterbalanced by the presence of the intermolecular H bond network. The hybrid materials have therefore a reversible behavior, thanks to h bonds behaving as molecular springs. For higher pressure ranges inorganic network start to be strongly impacted in a dominant way so that an irreversible loss of long range order within the organic network is observed.In a second time, the influence of the nature of the organic substructure (thiourea versus urea link, aryl versus aliphatic core) on this spring behavior is discussed.

Ref HAL: hal-01902659_v1
DOI: 10.1016/j.polymertesting.2018.07.007
WoS: 000445993600024
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3 Citations
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The degree of curing of epoxy composites and coatings is one key parameter to control the reliability of manufacturing processes, particularly in printed circuit board (PCB) manufacturing where epoxy buildup composites are partially cured before processing. We show that the reaction of curing of an industrially relevant buildup composite (epoxy-phenol reinforced with silica fillers) can be monitored by diffuse reflectance infrared Fourier transform (DRIFT) in the near-infrared range. The accuracy of DRIFT measurements is confirmed by comparison with measurements in transmission mode on reference composite samples. DRIFT is demonstrated to offer an easy and reliable measurement of the epoxy degree of curing on PCB coupons.

Ref HAL: hal-01884447_v1
DOI: 10.1021/acs.nanolett.8b02437
WoS: WOS:000441478300097
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16 Citations
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Mechanical resonators based on a singlecarbon nanotube are exceptional sensors of mass and force.The force sensitivity in these ultralight resonators is oftenlimited by the noise in the detection of the vibrations. Here,we report on an ultrasensitive scheme based on a RLCresonator and a low-temperature amplifier to detect nanotubevibrations. We also show a new fabrication process ofelectromechanical nanotube resonators to reduce the separation between the suspended nanotube and the gate electrodedown to ∼150 nm. These advances in detection and fabrication allow us to reach 0.5pm/ Hz displacement sensitivity.Thermal vibrations cooled cryogenically at 300 mK are detected with a signal-to-noise ratio as high as 17 dB. We demonstrate4.3zN/ Hz force sensitivity, which is the best force sensitivity achieved thus far with a mechanical resonator. Our work is animportant step toward imaging individual nuclear spins and studying the coupling between mechanical vibrations and electronsin different quantum electron transport regimes.

Ref HAL: hal-01845473_v1
DOI: 10.23647/ca.md20180407
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Single-walled carbon nanotubes are functionalized with copper hexacyanoferrate nanoparticles for the liquid-solid extraction of cesium from liquid waste and contaminated water. The functionalization process is followed mainly by x-ray photoemission spectroscopy. Indeed, determining the chemical environment around carbon or nitrogen atoms allows to evidence the formation of covalent bounding. In addition, the signatures of iron and copper ions give information on the effective growth of hexacyanoferrate nanoparticles. Furthermore, the cesium sorption mechanism is investigated by comparing the peak intensities associated to the response of potassium and cesium ions. Finally, based on the liquid chromatography analyzes, the sorption of cesium with the functionalized carbon supports is studied. The main results of this work are the demonstration of both a good selectivity of cesium trapping and a high sorption capacity by hybrid single-walled carbon nanotubes.

Ref HAL: hal-01844602_v1
Ref Arxiv: 1712.01055
DOI: 10.1103/PhysRevE.98.012605
WoS: 000439065200005
Ref. & Cit.: NASA ADS
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6 Citations
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The number of precise conductance measurements in nanopores is quickly growing. To clarify the dominant mechanisms at play and facilitate the characterization of such systems for which there is still no clear consensus, we propose an analytical approach to the ionic conductance in nanopores that takes into account (i) electro-osmotic effects, (ii) flow slip at the pore surface for hydrophobic nanopores, (iii) a component of the surface charge density that is modulated by the reservoir pH and salt concentration cs using a simple charge regulation model, and (iv) a fixed surface charge density that is unaffected by pH and cs . Limiting cases are explored for various ranges of salt concentration and our formula is used to fit conductance experiments found in the literature for carbon nanotubes. This approach permits us to catalog the different possible transport regimes and propose an explanation for the wide variety of currently known experimental behavior for the conductance versus cs .

Ref HAL: hal-01829525_v1
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Les nanotubes de carbone monofeuilltes (SWCNT) sont fonctionnalisés avec des nanoparticules d'hexacyanoferrate de cuivre (CuHCF) pour préparer des substrats solides pour la sorption des ions de césium (Cs +) des écoulements de liquide. La haute résistance mécanique et la grande conductivité électrique des SWCNT sont associées à la capacité des nanoparticules de CuHCF à complexer sélectivement les ions Cs + afin de réaliser des buckypapers de type membrane présentant une capacité de charge élevée du césium. Les matériaux sont soigneusement caractérisés en utilisant la microscopie électronique, la diffusion Raman, la spectroscopie de photoélectrons X et les analyses thermogravimétriques. Les isothermes de sorption de Cs sont portées après avoir mesuré la concentration en Cs + par chromatographie ionique en phase liquide dans la solution avant et après l'exposition aux matériaux. On trouve que la capacité totale de sorption du matériau atteint 230 mg.g-1, et qu'environ un tiers du Cs sorbé (80 mg.g-1) est sélectivement complexé dans les nanoparticules de CuHCF greffées sur SWCNTs. Les valeurs ouvrent des perspectives intéressantes dans l'intégration de tels matériaux dans des dispositifs de sorption et de désorption contrôlée de ces ions.

Ref HAL: hal-01829522_v1
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Single-walled carbon nanotubes (SWCNTs) are functionalized with copper hexacyanoferrate (CuHCF) nanoparticles to prepare solid substrates for the sorption of cesium ions (Cs+) from liquid outflows. The high mechanical resistance and large electrical conductivity of SWCNTs are associated to the ability of CuHCF nanoparticles to selectively complex Cs+ ions in order to achieve membrane-like buckypapers presenting high loading capacity of cesium. The materials are thoroughly characterized using electron microscopy, Raman scattering, X-ray photoelectron spectroscopy and thermogravimetric analyses. Cs sorption isotherms are plotted after having measured the Cs+ concentration by liquid phase ionic chromatography in the solution before and after exposure to the materials. It is found that the total sorption capacity of the material reaches 230 mg.g-1, and that about one third of the sorbed Cs (80 mg.g-1) is selectively complexed in the CuHCF nanoparticles grafted on SWCNTs.1 These high values open interesting outlooks in the integration of such materials in devices for the controlled sorption and desorption of these ions.