In this work we have carried out variable-load indentation testing on three sodium borosilicate glassesand characterized the indentation imprints using Raman spectroscopy. The resulting analysis of thespectra helps describe the relative amount of densification and shear ow appearing in each glass, as wellas the different microstructural mechanisms that take place during deformation. Additionally, we showthat the two glasses that are relatively poor in sodium exhibit enhanced mixing of the silicate and borateunits after indentation. For the indentations performed using the highest load, we also acquired spectraby focusing at various depths below the imprint, in order to characterize the deformed region of theglasses and estimate its size. Similar experiments have been also carried out for one of the three glassesafter neutron irradiation, in order to study the effects of mechanical deformation on its depolymerizedand swollen structure.

The recycling process toward the elimination of varistor wastes into new electro-active silicon composites has been investigated. We studied the dependence of the E-J characteristics on the aggregate content in the polymer matrix. Formulations with 40 vol.% metal oxide varistor aggregates in the 100-200m range exhibit reliable nonlinear behavior with a switching voltage of 280 +/- 30V/mm. The breakdown voltage of the composite decreases as both filler's diameter and filler's volume fraction increases in the 550-220V/mm and 440-280V/mm range, respectively. This paves the way for the valorization of varistors based zinc oxide (ZnO) ceramics.

In situ and ex situ Raman measurements were used to study the dynamics of the populations of single-walled carbon nanotubes (SWCNTs) during their catalytic growth by chemical vapor deposition. Our study reveals that the nanotube diameter distribution strongly evolves during SWCNT growth but in dissimilar ways depending on the growth conditions. We notably show that high selectivity can be obtained using short or moderate growth times. High-resolution transmission electron microscopy observations support that Ostwald ripening is the key process driving these seemingly contradictory results by regulating the size distribution and lifetime of the active catalyst particles. Ostwald ripening appears as the main termination mechanism for the smallest diameter tubes, whereas carbon poisoning dominates for the largest ones. By unveiling the key concept of dynamic competition between nanotube growth and catalyst ripening, we show that time can be used as an active parameter to control the growth selectivity of carbon nanotubes and other 1D systems.

We show that the properties of thin conductive inkjet printed lines of single-walled carbon nanotubes (SWCNT) can be greatly tuned, using only a few deposition parameters. The morphology, anisotropy and electrical resistivity of single-stroke printed lines are studied as a function of ink concentration and drop density. An original method based on coupled profilometry-Raman measurements is developed to determine the height, mass, orientational order and density profiles of SWCNT across the printed lines with a micrometric lateral resolution. Height profiles can be tuned from 'rail tracks' (twin parallel lines) to layers of homogeneous thickness by controlling nanotube concentration and drop density. In all samples, the nanotubes are strongly oriented parallel to the line axis at the edges of the lines, and the orientational order decreases continuously towards the center of the lines. The resistivity of 'rail tracks' is significantly larger than that of homogeneous deposits, likely because of large amounts of electrical dead-ends.

The experimental approach combining high resolution transmission electron microscopy (HRTEM), electron diffraction (ED) and resonant Raman spectroscopy (RRS) on the same free-standing individual carbon nanotubes (CNT) is the most efficient method to determine unambiguously the intrinsic features of the Raman-active phonons. In this paper, we review the main results obtained by the approach regarding the intrinsic features of the phonons of single-walled (SWNT) and double-walled carbon nanotubes (DWNT). First, we detail the different methods to identify the structure of SWNTs and DWNTs from the analysis of their electron diffraction patterns (EDP). In the following, we remind the principal features of the Raman response of SWNTs, unambiguously index-identified by ED. A special attention is devoted to the effect of the inter-layer interaction on the frequencies of the Raman-active phonons in index-identified DWNTs. The information obtained on index-identified SWNT and DWNT allows us to propose Raman criteria, which help identifying CNT when the ED fails to propose a single assignment. The efficiency of the Raman criteria as the complement to the ED information for the index-assignment of a few SWNTs and DWNTs is shown. The same approach to index-assign a triple-walled carbon nanotube (TWNT), by combining ED and RRS information, is reported.

Chalcogenide glasses and more importantly their glass-ceramics counterparts have been an interesting but very peculiar class of thermoelectric materials, with inherently low thermal conductivity (< 0.3 W/m.K). In this study, we report on the fabrication of glasses in the ternary system Cu-As-Te (Cu_xAs_55-xTe₄₅ [5 ≤ x ≤ 20], Cu₁₅As_85-yTe_y [45 ≤ y ≤ 70], and Cu₂₀As_80-yTe_y [45 ≤ y ≤ 65]) by melt-quenching and subsequent spark plasma sintering treatment. Their thermal and structural properties have been studied by differential scanning calorimetry and Raman spectroscopy, leading to give insights into the structural evolution of the glassy matrix. Coupling this information with the analysis of their electrical transport properties allowed us to deepen further our understanding of the compositional effect on their thermoelectric properties, and indirectly how the evolution of their electronic band structure is at play. Despite exhibiting low ZT values by themselves, Cu-As-Te glasses may still be interesting candidates for thermoelectricity through partial crystallization for which knowing the relationship between composition and properties remains essential.