We study the intrinsic Raman signatures of single layer graphene (SLG) dispersed in degassed water without additives, so called ‘‘eau de graphene” (EdG) and compare them to those of suspended SLG. The Raman signatures of SLG superimpose to those of water. The most characteristic signature of SLG in EdG is a narrow and symmetric 2D band with a width depending on processing conditions. The position of the G and 2D bands indicate moderate biaxial compressive strain and weak n doping. The intensity of the D band and the width of the G band are discussed in terms of point-defect density and flake size. We show that point defects can be easily cured by preparing thin films from EdG and annealing at 800°C.

We have carried out combined classical and ab initio molecular dynamics (MD)simulations in order to investigate the structural and vibrational properties of severalborosilicate glasses. We have considered rather simple ternary compositions withvarying SiO 2 , B 2 O 3 or Na 2 O concentrations, or more complex compositionscontaining equally CaO, Al 2 O 3 or MgO. The ab initio calculations have been carriedout within the density functional theory framework as implemented in the VASPcode. The classical MD simulations were carried out using different effective pairpotentials.We have studied the local structure of the various structural units, and inparticular we have focused on the structures around the boron atoms and how theseare embedded into the network. We have investigated how the Na atoms aredistributed around the [3] B triangles and [4] B tetrahedra. Furthermore, we have foundthat the Na distribution associated to a BO 4 tetrahedron is different from thatcorresponding to a SiO 4 tetrahedron in that the former gives rise to a distribution thatis significantly more structured.The vibrational properties have been equally studied within the ab initio approach,and we have identified the contributions of the various species as well as those ofthe local structural units. We have also calculated the dielectric function ε(ω) as wellas the absorption spectra. The latter are in good quantitative agreement withexperimental data. The results obtained in this work confirm that the atomisticsimulations, in particular the ab initio ones, give access to a better understanding ofcomplex borosilicate glasses since their structural and vibrational properties can beextracted with a good accuracy and compare very well to experimental data.

We have parameterized empirical potentials for molecular dynamics (MD) simulations ofmulti-component silicate glasses. The main motivation has been to improve predictions ofstatic properties like elastic moduli and dynamic properties like vibrational density of states(VDOS) that MD simulations have generally not been able to estimate correctly, while stillusing a simple functional form for computational efficiency.Our approach has been to fit the potentials to data extracted from accurate first principlescalculations to predict both the static and dynamic properties correctly, by explicitly incor-porating the radial distribution function (RDF) and the VDOS into the cost function of thefitting scheme. The current optimization scheme is an extension of a recent work using asinput only the structural data from the ab initio simulations, and which has been applied inthe past to obtain a reliable potential for amorphous silica [1,2].The newly developed potentials will be used to study the elastic response of multi-componentoxide glasses to external stimuli such as high temperatures, high pressures and high strains,and their deformation modes under different loading conditions.A. Carré, J. Horbach, S. Ispas, W. Kob, Europhys. Lett. 82 (2008) 17001.A. Carré, S. Ispas, J. Horbach, W. Kob, Comput. Mater. Sci. 124 (2016) 323

Curing kinetics of an industrially important printedcircuitboard (PCB) base material (epoxy–phenol/glass fillers)were studied by isothermal differential scanning calorimetry(DSC) measurements between 150 and 190°C, as relevant curingtemperatures for the PCB industry. The extent of cure was calculatedby integration of the exothermic peak and normalizationby the total heat of reaction (obtained by nonisothermal DSC).Although the cross-linking was completed above 180°C, thekinetic profiles show two regimes: one fast and one slow. Thekinetic parameters have been elucidated using an isoconversionalmodel-free kinetic method, with the exact method of Friedman,to give to the PCB manufacturers a road map to predict curingbehavior of base material. The linearity of Arrhenius plots wassatisfactory. The apparent activation energy of curing reactionhas been found to increase with the degree of conversion. Theelucidation of the kinetic parameters allows us to propose anaccurate and predictive description of the curing kinetics withinthe fast regimen of reaction (i.e., without vitrification). Finally,we discuss how these kinetic measurements and models can becompleted and optimized.

We simulated the low temperature (T = 77 K) hydrogen adsorption in carbon slit-shaped nanopores using consecutively united atom (UA) and all atom (AA) representation of hydrogen molecule. We showed that both approximations give comparable estimation of the amount stored, for the wide range of pore width (0.6-2.5 nm). We also showed that at very high pressure (P = 400 bar, corresponding to the fugacity f used in grand canonical Monte Carlo simulations of f = 800 bar) the density of the adsorbed hydrogen structures is larger than the density of bulk liquid at critical temperature (∼76 kg/m3). This result agrees with the experimental observation of the density of the order of 100 kg/m3 for the hydrogen adsorbed in microporous carbons, reported recently in the literature.