Recycling route toward electro-active silicone composites has been explored. We studied the dependence of the E-J characteristics on the aggregate content in the polymer matrix. Formulations with 35 vol.% MOV aggregates in the 200-375 µm range exhibit reliable nonlinear behavior with a switching voltage of 175 ± 30 V/mm. This opens a way to valorize varistors based on zinc oxide (ZnO) ceramics.

Infrared response on a carbon nanotube is weak because this homonuclear allotrope of carbon does not bear permanent dipoles. Here, we report the discovery of an exaltation of the infrared absorption response in single-walled carbon nanotubes from dye molecule interactions. A study performed on dimethylquaterthiophene confined into the hollow core of single-walled carbon nanotubes or π-stacked at the outer surface of the latter leads to a symmetry breaking, allowing us to probe interactions between both subsystems. The nature of these interactions is discussed taking into account the tube diameter. This new phenomenon opens a new route to detect weak vibrations thanks to a confinement effect.

We synthesized KC8 by simply mixing molten potassium and graphite at 180 °C under inert atmosphere. The KC8 showstypical shiny bronze color, Raman characteristics and XRD pattern of an efficiently intercalated stage 1 GIC, and is ofsufficient quality to produce fully exfoliated graphenide solutions in tetrahydrofuran (THF) and subsequently single layer graphene in water as “eau de graphene” (EdG). The evolution of absorption and Raman spectroscopic signatures of the EdGas a function of processing conditions give key indications on the number of layers of the graphene flakes dispersed in EdG.

We report on the preparation of a hybrid nanomaterial made up of 1D filaments of an antiferromagnetic self-assembling bicopper complex encapsulated in polymer nanofibrils. The encapsulation process is achieved through the heterogeneous nucleation of the growth of polymer fibrils obtained by thermoreversible gelation as shown by calorimetry experiments. Neutron scattering experiments confirm that the filaments of a bicopper complex retain their 1D character after encapsulation in the fibrils. Superconducting quantum interference device experiments show that the bicopper complex, originally in the gapped spin state in the 3D bulk mesophase, displays a gapless behavior once encapsulated. Extended absorption fine structure and infrared results further highlight the difference in the molecular arrangement of the bicopper complex between the bulk mesophase and the encapsulated state, which may account for the magnetic behavior. This material, which is largely disordered, differs totally from the usual magnetic systems where this effect is observed only on highly crystalline systems with long-range order. Also, this hybrid material is very easy to prepare from its basic constituents and can be further processed in many ways.

We report a detailed Raman study of single layergraphene dispersed in degassed water without additives (SLGiw), so-called “‘eau de graphene”’ (EdG).23 The most characteristic signature of SLGiw is a narrow (28 ± 2 cm−1) and symmetric 2D band. The intensity of the D band is dominated by the contribution of sp3 defects due to slight functionalization of the basal-planes. The density of defects is estimated in the range 200-650 ppm by studying thin films prepared from EdG. These defects can be fully and easily cured by annealing the films at 800 °C. The position of the G and 2D bands, blue-shifted with respect to pristine SLG, are assigned to moderate biaxial compressive strain (≈0.09 ± 0.02%) and likely weak n doping (<4 × 1012 electrons/cm2) of SLGiw.

Dispersing graphite in water to obtain true (single-layer) graphene in bulk quantity in a liquid has been an unreachablegoal for materials scientists in the past decade. Similarly, a diagnostic tool to identify solubilized graphene in situ has beenlong awaited. Here we show that homogeneous stable dispersions of single-layer graphene (SLG) in water can be obtainedby mixing graphenide (negatively charged graphene) solutions in tetrahydrofuran with degassed water and evaporatingthe organic solvent. In situ Raman spectroscopy of these aqueous dispersions shows all the expected characteristics ofSLG. Transmission electron and atomic force microscopies on deposits confirm the single-layer character. The resultingadditive-free stable water dispersions contain 400 m2 l–1 of developed graphene surface. Films prepared from thesedispersions exhibit a conductivity of up to 32 kS m–1.

Opto-electronic properties of single-walled carbon nanotubes can be significantly modified by chromophore confinement into their hollow core. This study deals with quaterthiophene derivatives encapsulated into nanotubes displaying different diameter distributions. We report a significant electron transfer from the confined molecules to the nanotubes in our hybrid systems, evidenced by photoluminescence and Raman investigations. This charge transfer leads to an important enhancement of the photoluminescence intensity by a factor of nearly five depending on the tube diameter. Energy shifts observed on both absorption and emission on the hybrid system also depend on the nanotube diameters and are interpreted in terms of local structure of the confined molecules. The Raman G-band of hybrid systems exhibits a drop in intensity and significant shifts whose magnitude and direction strongly depend on the nanotube diameter. These behaviors are consistent with a weak electron transfer from the molecule to the tube, in good agreement with the PL analysis. In addition, close to the molecule resonance, the magnitude of the G-band shifts are modified and the intensity loss is amplified, strongly suggesting a photo-induced electron transfer. Finally, the Breit-Wigner-Fano lineshape (characteristic of electron-phonon coupling) of the Raman G-band is strongly reduced for defective metallic nanotubes. After molecule functionalization, this peculiar profile is recovered, suggesting a back donation of electrons to the nanotube. Thus, confinement species into nanotubes allow moving the Fermi level and consequently to monitor their opto-electronic properties.