In this work, we explore the preparation and deposition of graphene oxide (GO)-metal (gold and palladium) nanoparticles (NPs) composites as thin films via wet routes. The properties of such films are examined, in view of Surface Enhanced Raman Spectroscopy (SERS) applications and as adhesion promoter thin films. It has been indeed shown that the encapsulation of metal NP within a few layers of graphene greatly improves the stability, reproducibility and sensitivity of SERS effect [1]. On the other hand, graphene oxide films decorated with metal nanoparticles are good non-etching adhesion promotors candidates for electroless deposition of metal thin films on non-metal substrates like glass or polymers [2, 3]. We discuss the preparation of the suspensions and the parameters (GO dispersion concentration, withdrawal speed and immersion time, functionalization of the substrates) which permit a good control of the deposition by dip-coating. The structure of the resulting thin films is characterized by Atomic Force Microscopy (AFM), Phase Shifting Interferometry (PSI) and Raman spectroscopy to determine the topography, thickness and homogeneity of the deposited layers. Their SERS and adhesion properties are then discussed.References[1] Y. Liu, Y. Hu, and J. Zhang, J. Phys. Chem. C, 2014, 1187, p. 8993‑ 8998.[2] S. P. Koenig, N. G. Boddeti, M. L. Dunn, and J. S. Bunch,2011, Nat. Nanotechnol.,6, p. 543‑ 546.[3] Q. Ma, X. Zhu, D. Zhang, and S. Liu, 2014, J. Mater. Chem. C,22, p. 8956‑ 8961.

We explore the preparation and use of graphene dispersions and graphene-nanoparticles composites viawet routes in order to create organized thin films (for passivation, adhesion and design of SERS substrates, seeFig.) At large concentrations, the liquid crystal ordering is an opportunity to spontaneously organize the materials.At lower concentrations, a special care has to be taken during the deposition of the thinnest films.In this work, we have focused on the design and the characterization of thin layers made of graphene oxide andgold nanoparticles (GO/AuNps) for their Surface Enhanced Raman Spectroscopy (SERS) properties. The objectivehere is to establish the main rules that control (during the deposition) the structure of the films and their resultingSERS properties. We have used various techniques such as dip-coating, spin coating with varying parameters, aswell as surface functionalization before deposition. The thin films have been characterized by AFM and theirperformance have been tested with Raman spectroscopy.

Graphene oxide dispersions are easily obtained in water. Due to the high aspect ratio of the flakes, liquid crystalsthen forms a nematic phase at moderate concentrations [1,2], which allows to design various composites withnanoparticles. Preparing organized materials and thin films from these dispersions however requires a good controlof the liquid crystal ordering during the deposition and the drying of the films.Here we have focused on mechanical instabilities that are frequently observed in thin graphene liquid crystallayers, when they are submitted to weak constraints. We have shown how to create and stabilize large-sizedperiodic textures (millimeter scale, see fig.1). The patterns have been characterized under optical and electronicmicroscopies. They result from the peculiar elastic and rheological properties of the graphene oxide liquid crystals.Our results also clarify why long-standing hypotheses on the presence of exotic phases [1] at large concentrationsare present in the literature.

The main hurdle preventing the widespread useof single-walled carbon nanotubes remains the lack ofmethods with which to produce formulations of pristine,unshortened, unfunctionalized, individualized single-walledcarbon nanotubes, thus preserving their extraordinary properties.In particular, sonication leads to shortening, which isdetrimental to percolation properties (electrical, thermal,mechanical, etc.). Using reductive dissolution and transfer intodegassed water, open-ended, water-filled nanotubes can bedispersed as individualized nanotubes in water−dimethylsulfoxide mixtures, avoiding the use of sonication andsurfactant. Closed nanotubes, however, aggregate immediately upon contact with water. Photoluminescence andabsorption spectroscopy both point out a very high degree of individualization while retaining lengths of several microns.The resulting transparent conducting films are 1 order of magnitude more conductive than surfactant-based blanks atequal transmittance.

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.

Despite an abundant literature on epoxy-amine systems, a complete description of the curing kinetics in epoxy-phenol composites was still lacking. In this study, the curing kinetics of an epoxy-phenol composite relevant to microelectronics industry is probed by isothermal and non-isothermal differential scanning calorimetry. An isoconversional analysis of the data reveals a significant contribution of the diffusion of molecular species to the activation energy, at low temperature and high degrees of curing. A model-fitting of the kinetics is performed in two successive steps: high-temperatures data are fitted with Arrhenius law and nth order autocatalytic model (where the diffusion contribution is neglected), whereas low-temperature data are fitted using Rabinowitch and modified-Williams-Landel-Ferry models (considering a diffusion contribution related to the glass transition). The chemical and diffusion contributions to the rate constants are calculated at various temperatures, clarifying the kinetics regimes with precision. Finally, the kinetics regimes are summarized in an improved time-temperature-transformation diagram.