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Plasma polymerized organosilicon thin films were deposited in a MW-PECVD using hexadimethylsiloxane (HMDSO) as a precursor. Thin films were synthetized with different plasma conditions ranging from soft (low plasma energy) to hard (high plasma energy) ones. Quantitative 29Si solid state NMR and FTIR spectroscopy were used to characterize the bulk composition. X-ray photoelectron spectroscopy (XPS) coupled with Density functional theory (DFT) calculations were used to determine the surface chemical composition. The bulk and the surface of the plasma polymerized HMDSO (PP-HMDSO) showed a complex chemical composition. The four main environments M, D, T and Q were present in the films. An additional environment Si(CH2)(CH3)3 denoted S was detected in the PP-HMDSO films. The chemical composition comparison showed a difference between the bulk and the surface of the films. Under soft plasma conditions, a high amount of SiOC3 termination was present in the bulk of the films. While, the SiO2C2 chains were highly present on the surface. On the other hand, under hard plasma conditions, the number of the SiOC3 termination increased on the surface and decreased in the bulk. Under soft plasma conditions, the PP-HMDSO structure was close to PDMS, while under hard plasma conditions, the PDMS similarity was lost.
Ghadi Dakroub; Thomas Duguet; Jérôme Esvan; Corinne Lacaze-Dufaure; Stéphanie Roualdes; Vincent Rouessac. Comparative study of bulk and surface compositions of plasma polymerized organosilicon thin films. Surfaces and Interfaces 2021, 25, 101256 .
AMA StyleGhadi Dakroub, Thomas Duguet, Jérôme Esvan, Corinne Lacaze-Dufaure, Stéphanie Roualdes, Vincent Rouessac. Comparative study of bulk and surface compositions of plasma polymerized organosilicon thin films. Surfaces and Interfaces. 2021; 25 ():101256.
Chicago/Turabian StyleGhadi Dakroub; Thomas Duguet; Jérôme Esvan; Corinne Lacaze-Dufaure; Stéphanie Roualdes; Vincent Rouessac. 2021. "Comparative study of bulk and surface compositions of plasma polymerized organosilicon thin films." Surfaces and Interfaces 25, no. : 101256.
This article describes the synthesis of a new bio-based organocatalytic surfactant. The nine steps of the synthesis were optimized, fully respecting the principles of green chemistry. The surfactant aspect was then evaluated with the use of tensiometric studies. The molecular organization of the surfactant in vesicles in an aqueous medium was characterized by Dynamic Light Scattering (DLS) and confirmed using Density Functional Theory (DFT) modelling.
Clément Giry; David Bertrand; Alexandre Pierret; Emeline Vedrenne; Corinne Lacaze-Dufaure; Jean-François Fabre; Sophie Thiebaud-Roux; Carlos Vaca Garcia; Christine Cecutti. Synthesis and Characterization of a New Organocatalytic Biosourced Surfactant. Sustainable Chemistry 2021, 2, 335 -342.
AMA StyleClément Giry, David Bertrand, Alexandre Pierret, Emeline Vedrenne, Corinne Lacaze-Dufaure, Jean-François Fabre, Sophie Thiebaud-Roux, Carlos Vaca Garcia, Christine Cecutti. Synthesis and Characterization of a New Organocatalytic Biosourced Surfactant. Sustainable Chemistry. 2021; 2 (2):335-342.
Chicago/Turabian StyleClément Giry; David Bertrand; Alexandre Pierret; Emeline Vedrenne; Corinne Lacaze-Dufaure; Jean-François Fabre; Sophie Thiebaud-Roux; Carlos Vaca Garcia; Christine Cecutti. 2021. "Synthesis and Characterization of a New Organocatalytic Biosourced Surfactant." Sustainable Chemistry 2, no. 2: 335-342.
A metal–polymer interface is pertinent to numerous technological applications, especially in spatial sectors. The focus of this work is to elaborate on the metallization process of the poly-epoxy surface with aluminum thin films, using atomistic details. To this end, X-ray photoelectron spectroscopy (XPS) under ultrahigh vacuum and density functional theory calculations are employed. The interfacial bonding between Al atoms and the poly-epoxide surface, represented by a dimer model, is studied by determining adsorption energies and by simulating XPS spectra. The latter simulations are mainly performed using the ΔKS method, taking into account the initial and the final state effects. Simulated atom-by-atom metal deposition on model epoxy systems is attempted to further elucidate energetics of metallization and preferential arrangement of metal atoms at the interface. A fair agreement obtained between XPS experiments and computations rationalizes the interaction mechanism at the atomic scale explaining the formation of the Al/poly-epoxy interface. Electronic structure properties highlight the charge transfer from the Al atom(s) to dehydrogenated model epoxy system.
Kanika Anand; Thomas Duguet; Jérôme Esvan; Corinne Lacaze-Dufaure. Chemical Interactions at the Al/Poly-Epoxy Interface Rationalized by DFT Calculations and a Comparative XPS Analysis. ACS Applied Materials & Interfaces 2020, 12, 57649 -57665.
AMA StyleKanika Anand, Thomas Duguet, Jérôme Esvan, Corinne Lacaze-Dufaure. Chemical Interactions at the Al/Poly-Epoxy Interface Rationalized by DFT Calculations and a Comparative XPS Analysis. ACS Applied Materials & Interfaces. 2020; 12 (51):57649-57665.
Chicago/Turabian StyleKanika Anand; Thomas Duguet; Jérôme Esvan; Corinne Lacaze-Dufaure. 2020. "Chemical Interactions at the Al/Poly-Epoxy Interface Rationalized by DFT Calculations and a Comparative XPS Analysis." ACS Applied Materials & Interfaces 12, no. 51: 57649-57665.
The reactivity of hydroxyquinoline derivatives (native molecules (Hq) and modified species (HqX, X = Br, SO3H, or SO3–)) is investigated either (i) with aluminum cations for the formation of chelates or (ii) with aluminum surfaces for their adsorption properties, in the framework of the dispersion-corrected Density Functional Theory (DFT-D). It is shown that the substituent X has no influence on the complexation to the aluminum cation of the deprotonated active form, i.e., the one exhibiting a phenolate moiety and referred to as q– for the native Hq and qXn– (n = 1 or 2) for its derivatives. The formation energies of the Alq3 and Al(qX)3 complexes, taking values of −60.87 ± 3.10 eV in vacuum and −24.30 ± 0.29 eV in water, are indicative of a strong chelating affinity of the q– and qXn– (n = 1 or 2) anions for the aluminum cations. ELF and QTAIM topological analyses on these complexes evidence that the bonding of the deprotonated species with the Al3+ ion is ionic with a very weak covalence degree. The para or ortho substituent X of the phenolate moiety of the qXn– (n = 1 or 2) derivatives modifies the electronic structure only locally and thus does not influence their O- or N-coordinating properties. The adsorption properties of the latter on an Al(111) surface have also been studied within periodic DFT-D calculations. The adsorbed species are strongly interacting with the Al(111) surface, as shown by the value of the adsorption energy of −3.69 ± 0.21 eV for the most stable geometries. Various adsorption modes of the q– and qXn– (n = 1 or 2) derivatives are characterized on the Al surface, depending on stabilizing or destabilizing interactions with the substituents X. On the basis of QTAIM descriptors, the bonding of the hydroxyquinoline species on the aluminum surface is characterized as ionic with a weak covalent character.
Yann Bulteau; Christine Lepetit; Corinne Lacaze-Dufaure. Topological Analysis of Hydroxyquinoline Derivatives Interacting with Aluminum Cations or with an Al(111) Surface. Inorganic Chemistry 2020, 59, 17916 -17928.
AMA StyleYann Bulteau, Christine Lepetit, Corinne Lacaze-Dufaure. Topological Analysis of Hydroxyquinoline Derivatives Interacting with Aluminum Cations or with an Al(111) Surface. Inorganic Chemistry. 2020; 59 (24):17916-17928.
Chicago/Turabian StyleYann Bulteau; Christine Lepetit; Corinne Lacaze-Dufaure. 2020. "Topological Analysis of Hydroxyquinoline Derivatives Interacting with Aluminum Cations or with an Al(111) Surface." Inorganic Chemistry 59, no. 24: 17916-17928.
8-Hydroxyquinoline (8Hq) is known to efficiently inhibit the corrosion of aluminium by forming metal–organic layers (8Hq forms complexes with aluminium atoms).
Yann Bulteau; Nathalie Tarrat; Nadine Pébère; Corinne Lacaze-Dufaure. 8-Hydroxyquinoline complexes (Alq3) on Al(111): atomic scale structure, energetics and charge distribution. New Journal of Chemistry 2020, 44, 15209 -15222.
AMA StyleYann Bulteau, Nathalie Tarrat, Nadine Pébère, Corinne Lacaze-Dufaure. 8-Hydroxyquinoline complexes (Alq3) on Al(111): atomic scale structure, energetics and charge distribution. New Journal of Chemistry. 2020; 44 (35):15209-15222.
Chicago/Turabian StyleYann Bulteau; Nathalie Tarrat; Nadine Pébère; Corinne Lacaze-Dufaure. 2020. "8-Hydroxyquinoline complexes (Alq3) on Al(111): atomic scale structure, energetics and charge distribution." New Journal of Chemistry 44, no. 35: 15209-15222.
Experiments and computations are performed in order to assess the interfacial bonding between Cu and a poly-epoxy surface relevant to many applications. The surface of the poly-epoxy is characterized by XPS and AFM before and after ultrahigh vacuum Cu deposition. Modifications of the XPS spectra are observed, suggesting a strong interaction between specific C and O atoms of the surface with Cu. DFT calculations are then performed to simulate XPS spectra and to better understand bonding. DFT computations are performed in the framework of the uGTS methodology which takes initial and final state effects into account, and allows to calculate chemical shifts between the different C1s and O1s molecular orbitals with a good accuracy, for the pristine surface. DFT calculations are then set to determine the preferential adsorption sites of Cu on different sites of the polymer surface. Finally, XPS simulation of the C1s and O1s spectra with Cu adsorbed at these sites match very well with the experimental spectra, indicating that Cu atoms interact preferentially with hydroxyls to form Cu-O-C bonds, stabilized by a transfer of 0.5 electrons from Cu to O, hence Cu is partially oxidized.
Thomas Gérald Duguet; Andreas Gavrielides; Jérôme Esvan; Tzonka Mineva; Corinne Lacaze-Dufaure. DFT Simulation of XPS Reveals Cu/Epoxy Polymer Interfacial Bonding. The Journal of Physical Chemistry C 2019, 123, 30917 -30925.
AMA StyleThomas Gérald Duguet, Andreas Gavrielides, Jérôme Esvan, Tzonka Mineva, Corinne Lacaze-Dufaure. DFT Simulation of XPS Reveals Cu/Epoxy Polymer Interfacial Bonding. The Journal of Physical Chemistry C. 2019; 123 (51):30917-30925.
Chicago/Turabian StyleThomas Gérald Duguet; Andreas Gavrielides; Jérôme Esvan; Tzonka Mineva; Corinne Lacaze-Dufaure. 2019. "DFT Simulation of XPS Reveals Cu/Epoxy Polymer Interfacial Bonding." The Journal of Physical Chemistry C 123, no. 51: 30917-30925.
Gas-Expanded Liquids have been studied during the last years, however, the physicochemical properties of some of these fluids still need to be characterized and understood. In particular, study of properties concerning solvation and mass transport are key for industrial applications. This work presents the characterization of eight CO2-expanded biosourced solvents: organic carbonates (dimethyl, diethyl, ethylene and propylene carbonates), anisole, veratrole, γ-valerolactone and 2-methyltetrahydrofuran. Two approaches have been used: spectroscopic measurements and molecular modelling. Phase equilibrium was determined for each CO2/biosourced solvent system, then the solvatochromic probe Nile Red was used to determine changes in dipolarity/polarizability (* Kamlet-Taft parameter) by CO2 pressure. Molecular dynamics calculations were performed to determine the density and viscosity changes with CO2 pressure. It is shown in this study that the degree of modulation of dipolarity/polarizability parameter can go from that of pure solvent (around 0.4 for linear organic carbonates) to negative values, close to that of pure CO2 at the T and P used in this study. Concerning transport properties density and viscosity, a great decrease was observed after swelling of the solvent by CO2, for instance, in linear organic carbonates where density can decrease to 50% the density of pure solvent; concerning viscosity a decrease of up to 90% was measured for these compounds. It was observed that solubility of CO2 and then modulation of properties was higher in linear organic carbonates than in the cyclic ones. This study shows once more that CO2 has great capacity to be used as a knob for triggering changes in the physicochemical properties of green biosourced solvents that can help to implement these solvents in industrial applications.
Emanuel Granero-Fernandez; Corinne Lacaze-Dufaure; Jean-Stéphane Condoret; Vincent Gerbaud; Yaocihuatl Medina-Gonzalez. Controlling Solvation and Mass Transport Properties of Biobased Solvents through CO2 Expansion: A Physicochemical and Molecular Modeling Study. Industrial & Engineering Chemistry Research 2019, 58, 18942 -18964.
AMA StyleEmanuel Granero-Fernandez, Corinne Lacaze-Dufaure, Jean-Stéphane Condoret, Vincent Gerbaud, Yaocihuatl Medina-Gonzalez. Controlling Solvation and Mass Transport Properties of Biobased Solvents through CO2 Expansion: A Physicochemical and Molecular Modeling Study. Industrial & Engineering Chemistry Research. 2019; 58 (41):18942-18964.
Chicago/Turabian StyleEmanuel Granero-Fernandez; Corinne Lacaze-Dufaure; Jean-Stéphane Condoret; Vincent Gerbaud; Yaocihuatl Medina-Gonzalez. 2019. "Controlling Solvation and Mass Transport Properties of Biobased Solvents through CO2 Expansion: A Physicochemical and Molecular Modeling Study." Industrial & Engineering Chemistry Research 58, no. 41: 18942-18964.
Polyepoxy samples are synthesized from diglycidylether of bisphenol A (DGEBA) and ethylene diamine (EDA) monomers at a stoichiometric ratio of 2 DGEBA : 1 EDA in model conditions in order to promote a high degree of polymerization and a low density of defects and to try to approach the ideal models obtained by simulation. A slow polymerization (>24 h at ambient temperature) and a postcuring achieved in an inert atmosphere lead to a conversion degree of 92±2% and a midpoint glass transition temperature of 391±1 K. In parallel, a model is created with a multistep cross-linking procedure. In this work, all-atom molecular dynamics (MD) simulations are performed with LAMMPS and the GAFF 1.8 force field. In the initial liquid mixture of reactants (600 molecules), proper mixing is demonstrated by the calculation of the partial radial distribution functions (RDF), which show a minimum intermolecular distance of 2.8 Å and similar distributions for EDA-EDA, DGEBA-DGEBA, and DGEBA-EDA molecules in the simulation boxes. Then, in alternation with MD equilibrations, cross-linking is performed on frozen configurations by creating covalent bonds between reactive pairs within a reaction radius of 3 Å. The resulting boxes show conversion rates of 90-93% and densities close to the experimental value. Finally, a cooling ramp from 700 K to 25 K is applied in order to monitor the specific volume and the coefficient of volumetric thermal expansion (CVTE) of the polymer and to derive the glass transition temperature. Experimental thermomechanical analyses (TMA) compares well with simulations for both the specific volume and the CVTE evolutions with temperature. Whereas the uncertainty remains high with the fitting procedure used, we calculate a glass transition temperature of 390±8 K which compares very well with the experimental values (391±1 K from DSC and 380 K from TMA).
Andreas Gavrielides; Thomas Duguet; Maëlenn Aufray; Corinne Lacaze-Dufaure. Model of the DGEBA-EDA Epoxy Polymer: Experiments and Simulation Using Classical Molecular Dynamics. International Journal of Polymer Science 2019, 2019, 1 -9.
AMA StyleAndreas Gavrielides, Thomas Duguet, Maëlenn Aufray, Corinne Lacaze-Dufaure. Model of the DGEBA-EDA Epoxy Polymer: Experiments and Simulation Using Classical Molecular Dynamics. International Journal of Polymer Science. 2019; 2019 ():1-9.
Chicago/Turabian StyleAndreas Gavrielides; Thomas Duguet; Maëlenn Aufray; Corinne Lacaze-Dufaure. 2019. "Model of the DGEBA-EDA Epoxy Polymer: Experiments and Simulation Using Classical Molecular Dynamics." International Journal of Polymer Science 2019, no. : 1-9.
The corrosion protective 8HQ monolayer on Al(111).
Fatah Chiter; Marie-Laure Bonnet; Corinne Lacaze-Dufaure; Hao Tang; Nadine Pébère. Corrosion protection of Al(111) by 8-hydroxyquinoline: a comprehensive DFT study. Physical Chemistry Chemical Physics 2018, 20, 21474 -21486.
AMA StyleFatah Chiter, Marie-Laure Bonnet, Corinne Lacaze-Dufaure, Hao Tang, Nadine Pébère. Corrosion protection of Al(111) by 8-hydroxyquinoline: a comprehensive DFT study. Physical Chemistry Chemical Physics. 2018; 20 (33):21474-21486.
Chicago/Turabian StyleFatah Chiter; Marie-Laure Bonnet; Corinne Lacaze-Dufaure; Hao Tang; Nadine Pébère. 2018. "Corrosion protection of Al(111) by 8-hydroxyquinoline: a comprehensive DFT study." Physical Chemistry Chemical Physics 20, no. 33: 21474-21486.
Different physicochemical properties of CO2-expanded alkyl acetates (methyl, ethyl, propyl et isoamyl acetates) have been studied by experimental and molecular modelling methods. Changes in *, (polarity/dipolarizability) Kamlet-Taft parameter with CO2 pressure were determined by UV-Vis spectroscopy by following the hypsochromic shift of Nile Red. Modelling of the systems by Molecular Dynamics (MD) and Equation of State (EoS) methods of physical equilibrium, density and of viscosity were performed in order to fully characterize these media with the aim to control the physicochemical properties of these phases by pressure and temperature. The studied expanded phases were used in the fabrication of TiO2 microparticules and the morphological properties measured. It is clear from this study that density, viscosity and polarity of the expanded phase plays a key role in the morphological properties of the particles obtained. Based on these results, we propose these green media and CO2 pressure as a way to control the properties of semiconductor microparticles.
Emanuel Granero-Fernandez; Devin Machin; Corinne Lacaze-Dufaure; Séverine Camy; Jean-Stéphane Condoret; Vincent Gerbaud; Paul A. Charpentier; Yaocihuatl Medina-Gonzalez. CO2-Expanded Alkyl Acetates: Physicochemical and Molecular Modeling Study and Applications in Chemical Processes. ACS Sustainable Chemistry & Engineering 2018, 6, 7627 -7637.
AMA StyleEmanuel Granero-Fernandez, Devin Machin, Corinne Lacaze-Dufaure, Séverine Camy, Jean-Stéphane Condoret, Vincent Gerbaud, Paul A. Charpentier, Yaocihuatl Medina-Gonzalez. CO2-Expanded Alkyl Acetates: Physicochemical and Molecular Modeling Study and Applications in Chemical Processes. ACS Sustainable Chemistry & Engineering. 2018; 6 (6):7627-7637.
Chicago/Turabian StyleEmanuel Granero-Fernandez; Devin Machin; Corinne Lacaze-Dufaure; Séverine Camy; Jean-Stéphane Condoret; Vincent Gerbaud; Paul A. Charpentier; Yaocihuatl Medina-Gonzalez. 2018. "CO2-Expanded Alkyl Acetates: Physicochemical and Molecular Modeling Study and Applications in Chemical Processes." ACS Sustainable Chemistry & Engineering 6, no. 6: 7627-7637.
The adsorption on anatase (101) TiO2 surface of two model amines, diaminoethane (DAE) and propylamine (PPA), was investigated using Density Functional Theory-Dispersion included (DFT-D) calculations. The investigated coverage is ranging from 0.25 monolayer to full coverage (one amine molecule per surface Ti ion). Both interactions of the adsorbed layer with the anatase (101) TiO2 surface and intermolecular interactions are described. A structural transition from a bridge to a perpendicular structure is found for DAE when evolving from 0.25 monolayer to full coverage. At full coverage, a dense, ordered adhesive layer is formed. For DAE, at intermediate coverage, different isoenergetic configurations are found and structural transition from a bridge to a perpendicular structure is found. In contrast, the adsorption mode of PPA is more regular with only perpendicularly adsorbed molecules at all investigated coverages. Dispersion forces already account for 40% of the adsorption energy at low coverage (0.25 ML) and are the driving force for monolayer formation with a contribution of 60% up to 100% at high coverage. As revealed by molecular dynamics, the molecules can change their orientation towards the surface in a concerted way.
A. Hemeryck; A. Motta; C. Lacaze-Dufaure; D. Costa; P. Marcus. DFT-D study of adsorption of diaminoethane and propylamine molecules on anatase (101) TiO 2 surface. Applied Surface Science 2017, 426, 107 -115.
AMA StyleA. Hemeryck, A. Motta, C. Lacaze-Dufaure, D. Costa, P. Marcus. DFT-D study of adsorption of diaminoethane and propylamine molecules on anatase (101) TiO 2 surface. Applied Surface Science. 2017; 426 ():107-115.
Chicago/Turabian StyleA. Hemeryck; A. Motta; C. Lacaze-Dufaure; D. Costa; P. Marcus. 2017. "DFT-D study of adsorption of diaminoethane and propylamine molecules on anatase (101) TiO 2 surface." Applied Surface Science 426, no. : 107-115.
International audienceThe valence and conduction bands of a thin film of tetra(4-aminophenyl)porphyrin (TAPP) are investi-gated by direct and inverse photoemission as well as by comparison to density functional theory (DFT)calculations. By projecting the electronic eigenfunctions onto the molecular framework it was possibleto interpret the origin of each spectroscopic feature. Although the majority of the photoemission spec-trum is attributed to the unsubstituted tetraphenylporphyrin (TPP) parent molecule, several featuresare clearly due to the amino substitution. Substitution also has important consequences for the energypositions of the frontier orbitals and therefore on the low-energy electronic excitations. The measuredelectronic transport energy gap (Eg= 1.85 eV) between the highest occupied molecular orbital (HOMO)and lowest unoccupied (LUMO) in TAPP is found to be significantly reduced with respect to TPP. More-over, an increased energy separation between the two highest occupied states (HOMO and HOMO−1) isfound both experimentally and by DFT calculations. Such evidence is attributed to an increased HOMOorbital destabilization due to an enhanced electron-donor character of the phenyl substituents uponamino functionalization. Finally, the above findings together with further time-dependent DFT calcula-tions are used to interpret the effect of the amino groups on the UV–Vis absorption spectrum, namely anoverall red-shift of the spectrum and remarkable intensity changes within the Q band
L. Giovanelli; H.-L. Lee; Corinne Lacaze-Dufaure; M. Koudia; Sylvain Clair; Y.-P. Lin; Y. Ksari; J.-M. Themlin; Mathieu Abel; A.A. Cafolla. Electronic structure of tetra(4-aminophenyl)porphyrin studied by photoemission, UV–Vis spectroscopy and density functional theory. Journal of Electron Spectroscopy and Related Phenomena 2017, 218, 40 -45.
AMA StyleL. Giovanelli, H.-L. Lee, Corinne Lacaze-Dufaure, M. Koudia, Sylvain Clair, Y.-P. Lin, Y. Ksari, J.-M. Themlin, Mathieu Abel, A.A. Cafolla. Electronic structure of tetra(4-aminophenyl)porphyrin studied by photoemission, UV–Vis spectroscopy and density functional theory. Journal of Electron Spectroscopy and Related Phenomena. 2017; 218 ():40-45.
Chicago/Turabian StyleL. Giovanelli; H.-L. Lee; Corinne Lacaze-Dufaure; M. Koudia; Sylvain Clair; Y.-P. Lin; Y. Ksari; J.-M. Themlin; Mathieu Abel; A.A. Cafolla. 2017. "Electronic structure of tetra(4-aminophenyl)porphyrin studied by photoemission, UV–Vis spectroscopy and density functional theory." Journal of Electron Spectroscopy and Related Phenomena 218, no. : 40-45.
Whereas poly-epoxy polymers represent a class of materials with a wide range of applications, the structural disorder makes them difficult to model. In the present work, we use good experimental model samples in the sense that they are pure, fully polymerized, flat and smooth, defect-free, and suitable for ultrahigh vacuum x-ray photoelectron spectroscopy, XPS, experiments. In parallel, we perform Hartree-Fock, HF, calculations of the binding energies, BEs, of the C1s electrons in a model molecule composed of the two constituents of the poly-epoxy sample. These C1s BEs were determined using the HF ΔSCF method, which is known to yield accurate values, especially for the shifts of the BEs, ΔBEs. We demonstrate the benefits of combining rigorous theory with careful XPS measurements in order to obtain correct assignments of the C1s XPS spectra of the polymer sample. Both the relative binding energies—by the ΔSCF method—and relative intensities—in the sudden approximation, SA, are calculated. It results in an excellent match with the experimental spectra. We are able to identify 9 different chemical environments under the C1s peak, where an exclusively experimental work would have found only 3 contributions. In addition, we observe that some contributions are localized at discrete binding energies, whereas others allow a much wider range because of the variation of their second neighbor bound polarization. Therefore, HF-ΔSCF simulations significantly increase the spectral resolution of XPS and thus offer a new avenue for the exploration of the surface of polymers.
A. Gavrielides; T. Duguet; J. Esvan; Corinne Lacaze-Dufaure; P. S. Bagus. A poly-epoxy surface explored by Hartree-Fock ΔSCF simulations of C1s XPS spectra. The Journal of Chemical Physics 2016, 145, 074703 .
AMA StyleA. Gavrielides, T. Duguet, J. Esvan, Corinne Lacaze-Dufaure, P. S. Bagus. A poly-epoxy surface explored by Hartree-Fock ΔSCF simulations of C1s XPS spectra. The Journal of Chemical Physics. 2016; 145 (7):074703.
Chicago/Turabian StyleA. Gavrielides; T. Duguet; J. Esvan; Corinne Lacaze-Dufaure; P. S. Bagus. 2016. "A poly-epoxy surface explored by Hartree-Fock ΔSCF simulations of C1s XPS spectra." The Journal of Chemical Physics 145, no. 7: 074703.
State-of-the-art van der Waals (vdW) corrected density functional theory (DFT) is routinely used to overcome the failure of standard DFT in the description of molecule/surface long range interactions. However, the systematic use of dispersion forces to model metallic surfaces could lead to less accurate results than the standard DFT and the effect of these corrections on the metal properties should be properly evaluated. In this framework, the behavior of two widely used vdW corrected DFT methods (DFT-D2 and vdW–DF/optB86b) has been evaluated on six metals, i.e. Al, Cu, Au, Ni, Co and Fe, with respect to standard GGA–DFT and experiments. Regarding bulk properties, general trends are found for the lattice parameter, cohesive energy and magnetic moment variations when the vdW correction is introduced. Surface energies, work functions and interlayer distances of closed packed surfaces, Al(111), Cu(111), Au(111) and magnetic Ni(111), Co(0001) and Fe(110), are also strongly affected by the dispersion forces. These modifications suggest a systematic verification of the surface properties when a dispersion correction is included.
Fatah Chiter; Van Bac Nguyen; Nathalie Tarrat; Magali Benoit; Hao Tang; Corinne Lacaze-Dufaure. Effect of van der Waals corrections on DFT-computed metallic surface properties. Materials Research Express 2016, 3, 046501 .
AMA StyleFatah Chiter, Van Bac Nguyen, Nathalie Tarrat, Magali Benoit, Hao Tang, Corinne Lacaze-Dufaure. Effect of van der Waals corrections on DFT-computed metallic surface properties. Materials Research Express. 2016; 3 (4):046501.
Chicago/Turabian StyleFatah Chiter; Van Bac Nguyen; Nathalie Tarrat; Magali Benoit; Hao Tang; Corinne Lacaze-Dufaure. 2016. "Effect of van der Waals corrections on DFT-computed metallic surface properties." Materials Research Express 3, no. 4: 046501.
The 8-hydroxyquinoline (8-HQ) molecule is an efficient corrosion inhibitor for aluminum and is also used in organic electronic devices. The 8-hydroxyquinoline (8-HQ) molecule is an efficient corrosion inhibitor for aluminum and is also used in organic electronic devices. In this paper, the adsorption modes of 8-HQ and its derivatives (tautomer, dehydrogenated and hydrogenated species) on the Al(111) surface are characterized using dispersion corrected density functional theory calculations. The 8-HQ molecule is physisorbed and is chemisorbed on the aluminum surface with similar adsorption energy (−0.86 eV to −1.11 eV) and these adsorption modes are stabilized by vdW interactions. The binding of the dehydrogenated species is the strongest one (adsorption energy of −3.27 eV to −3.45 eV), followed by the tautomer molecule (−2.16 eV to −2.39 eV) and the hydrogenated molecule (−1.71 eV) that bind weaker. In all the chemisorbed configurations there is a strong electronic transfer from the Al substrate to the adsorbate (0.72 e to 2.16 e). The adsorbate is strongly distorted and its deformation energy is high (0.55 eV to 2.77 eV). The analysis of the projected density of states onto the orbitals of the molecule and the electronic density variation upon adsorption (Δ ρ ) between the molecule and the surface account for covalent bonding.
Fatah Chiter; Corinne Lacaze-Dufaure; Hao Tang; Nadine Pébère. DFT studies of the bonding mechanism of 8-hydroxyquinoline and derivatives on the (111) aluminum surface. Physical Chemistry Chemical Physics 2015, 17, 22243 -22258.
AMA StyleFatah Chiter, Corinne Lacaze-Dufaure, Hao Tang, Nadine Pébère. DFT studies of the bonding mechanism of 8-hydroxyquinoline and derivatives on the (111) aluminum surface. Physical Chemistry Chemical Physics. 2015; 17 (34):22243-22258.
Chicago/Turabian StyleFatah Chiter; Corinne Lacaze-Dufaure; Hao Tang; Nadine Pébère. 2015. "DFT studies of the bonding mechanism of 8-hydroxyquinoline and derivatives on the (111) aluminum surface." Physical Chemistry Chemical Physics 17, no. 34: 22243-22258.
International audienceA model poly-epoxy surface formed by the reaction of DGEBA and EDA is studied by the combination of experiments and DFT calculations. A special synthesis protocol is presented leading to the formation of a surface that is smooth (S a < 1 nm), chemically homogeneous, and that presents a low-defect density (0.21 μm -2 ), as shown by AFM characterizations. Then, XPS is used for the determination of the elemental and functional groups’ surface composition. DFT allows the identification and assignment of individual bonds contributions to the experimental 1s core-level peaks. Overall, we demonstrate that such a model sample is perfectly suitable for a use as a template for the study of poly-epoxy surface functionalization
Thomas Duguet; Camille Bessaguet; Maëlenn Aufray; Jérôme Esvan; Cédric Charvillat; Constantin Vahlas; Corinne Lacaze-Dufaure. Toward a computational and experimental model of a poly-epoxy surface. Applied Surface Science 2015, 324, 605 -611.
AMA StyleThomas Duguet, Camille Bessaguet, Maëlenn Aufray, Jérôme Esvan, Cédric Charvillat, Constantin Vahlas, Corinne Lacaze-Dufaure. Toward a computational and experimental model of a poly-epoxy surface. Applied Surface Science. 2015; 324 ():605-611.
Chicago/Turabian StyleThomas Duguet; Camille Bessaguet; Maëlenn Aufray; Jérôme Esvan; Cédric Charvillat; Constantin Vahlas; Corinne Lacaze-Dufaure. 2015. "Toward a computational and experimental model of a poly-epoxy surface." Applied Surface Science 324, no. : 605-611.
Sugar cane is a crop which generates large amounts of biomass and a juice rich in high-value natural molecules. After extracting sugar from the juice, the recovering of various compounds such as organic acids contained in molasses could contribute to increase the competivity of the sugar industry. Therefore, according to the biorefinery approach, we propose to study the chemical conversion of one of these acids, the aconitic acid, by esterification reactions. A new series of aconitate esters have been synthesized by combining aconitic acid and alcohols from natural origin. The effects of experimental conditions have been investigated and have shown that the type of catalysis has a significant effect on the selectivity. Kinectics have thus been performed to determine the best conditions to synthetize enriched compositions in esters. Homogeneous catalysis generates the highest yield in triester. Heterogeneous catalysis (macroporous resins) is prefered for the production of monoesters while catalysis assisted by ionic liquid is adapted to prepare mainly diesters. Green indicators have been discussed according to the calculations performed. The resulting polyfunctional esters are totally biosourced molecules and have a great potential as bioproducts for different applications.
William Piang-Siong; Pascale de Caro; Corinne Lacaze-Dufaure; Alain Shum Cheong Sing; William Hoareau. Effect of catalytic conditions on the synthesis of new aconitate esters. Industrial Crops and Products 2012, 35, 203 -210.
AMA StyleWilliam Piang-Siong, Pascale de Caro, Corinne Lacaze-Dufaure, Alain Shum Cheong Sing, William Hoareau. Effect of catalytic conditions on the synthesis of new aconitate esters. Industrial Crops and Products. 2012; 35 (1):203-210.
Chicago/Turabian StyleWilliam Piang-Siong; Pascale de Caro; Corinne Lacaze-Dufaure; Alain Shum Cheong Sing; William Hoareau. 2012. "Effect of catalytic conditions on the synthesis of new aconitate esters." Industrial Crops and Products 35, no. 1: 203-210.
We report a density-functional study of some properties of the adsorption process of the NO molecule on small palladium clusters (n = 1–4). The interaction between NO and the Pdn clusters is studied on various adsorption sites. Both, NO and Pdn geometrical relaxations are taken into account. The significant conformational reconstruction of the metallic cluster upon NO adsorption induces a large decrease of the NO adsorption energy. Nevertheless, the N–O binding energy is strongly weakened when the molecule is adsorbed on the small Pdn clusters due essentially to an electrostatic repulsion between both N and O atoms. The possible dissociation process of NO on Pd4 cluster is then investigated within two processes: the NO molecule does not dissociate on Pd4 with process (i) (dissociation of the isolated gas phase NO molecule followed by the adsorption of both nitrogen and oxygen atoms on the cluster). Process (ii) which presents three successive steps (adsorption of the NO molecule, dissociation of the NO molecule adsorbed on Pd4, adsorption of the O atom on the cluster) is studied in details and we propose a reaction pathway locating transition states and intermediate species. The activation energy for process (ii) is high and the dissociation of the NO molecule on the Pd4 cluster is thus highly improbable.
C. Lacaze-Dufaure; J. Roques; C. Mijoule; E. Sicilia; N. Russo; V. Alexiev; Tzonka Mineva. A DFT study of the NO adsorption on Pdn (n=1–4) clusters. Journal of Molecular Catalysis A: Chemical 2011, 341, 28 -34.
AMA StyleC. Lacaze-Dufaure, J. Roques, C. Mijoule, E. Sicilia, N. Russo, V. Alexiev, Tzonka Mineva. A DFT study of the NO adsorption on Pdn (n=1–4) clusters. Journal of Molecular Catalysis A: Chemical. 2011; 341 (1-2):28-34.
Chicago/Turabian StyleC. Lacaze-Dufaure; J. Roques; C. Mijoule; E. Sicilia; N. Russo; V. Alexiev; Tzonka Mineva. 2011. "A DFT study of the NO adsorption on Pdn (n=1–4) clusters." Journal of Molecular Catalysis A: Chemical 341, no. 1-2: 28-34.
International audienceThe structural and electronic properties of Cu segregation in aluminum are studied in the framework of the density functional theory, within the projector augmented plane-wave method and both its local density approximation (LDA) and generalized gradient approximation (GGA). We first studied Al-Cu interactions in bulk phase at low copper concentration (≤3.12%: at). We conclude to a tendency to the formation of a solid solution at T=0 K. We moreover investigated surface alloy properties for varying compositions of a Cu doped Al layer in the (111) Al surface then buried in an (111) Al slab. Calculated segregation energies show unstable systems when Cu atoms are in the surface position (position 1). In the absence of ordering effects for Cu atoms in a layer (xCu=1/9 and xCu=1/3), the system is more stable when the doped layer is buried one layer under the surface (position 2), whereas for xCu=1/2 to xCu=1 (full monolayer), the doped layer is more accommodated when buried in the sub-sub-surface (position 3). First stage formation of GP1- and GP2-zones was finally modeled by doping (100) Al layers with Cu clusters in a (111) Al slab, in the surface then buried one and two layers under the surface. These multilayer clusters are more stable when buried one layer beneath the surface. Systems modeling GP1-zones are more stable than systems modeling GP2-zones. However the segregation of a full copper (100) monolayer in an (100) Al matrix shows a copper segregation deep in the bulk with a segregation barrier. Our results fit clearly into a picture of energetics and geometrical properties dominated by preferential tendency to Cu clustering close to the (111) Al surface
A. Benali; C. Lacaze-Dufaure; J. Morillo. Density functional study of copper segregation in aluminum. Surface Science 2011, 605, 341 -350.
AMA StyleA. Benali, C. Lacaze-Dufaure, J. Morillo. Density functional study of copper segregation in aluminum. Surface Science. 2011; 605 (3-4):341-350.
Chicago/Turabian StyleA. Benali; C. Lacaze-Dufaure; J. Morillo. 2011. "Density functional study of copper segregation in aluminum." Surface Science 605, no. 3-4: 341-350.
We study structural analogues of endoperoxides belonging to the family of G factors which present moderate to good antimalarial activity. Their biological activity is related to the reduction and cleavage of the O-O bond. Generally, the O-O bond reduction of model endoperoxides, as well as artemisinin, occurs by a concerted dissociative electron transfer (ET) mechanism. For the G3 and G3Me compounds, the experimental counterpart indicates an unexpected competition between a concerted and a stepwise mechanism, but no intermediate species can be isolated. We thus perform DFT studies on the reduction of G3 and G3Me compounds. We confirm the formation of an intermediate radical anion followed by cleavage of the O-O bond in a second step. We characterize the stable conformations for the radical anions G(3)(*-) and G(3)Me(*-) resulting from the ET and the associated reaction pathway. We also calculate the reorganization energy upon ET in relation to the Marcus theory using the DFT method. These results provide valuable insight into understanding the biological activity of G-factor endoperoxides as potential therapeutic antimalarial agents.
Corinne Lacaze-Dufaure; Fadia Najjar; Christiane André-Barrès. First Computational Evidence of a Competitive Stepwise and Concerted Mechanism for the Reduction of Antimalarial Endoperoxides. The Journal of Physical Chemistry B 2010, 114, 9848 -9853.
AMA StyleCorinne Lacaze-Dufaure, Fadia Najjar, Christiane André-Barrès. First Computational Evidence of a Competitive Stepwise and Concerted Mechanism for the Reduction of Antimalarial Endoperoxides. The Journal of Physical Chemistry B. 2010; 114 (30):9848-9853.
Chicago/Turabian StyleCorinne Lacaze-Dufaure; Fadia Najjar; Christiane André-Barrès. 2010. "First Computational Evidence of a Competitive Stepwise and Concerted Mechanism for the Reduction of Antimalarial Endoperoxides." The Journal of Physical Chemistry B 114, no. 30: 9848-9853.