M2 (MME) Matter, Molecules, and their Environments

• Theoretical approach to molecular spectroscopy (3 ECTS)
• Advanced characterization methods
  • Raman, infrared, dielectric and terahertz spectroscopies (3 ECTS)
  • X-ray diffraction and electron microscopy (3 ECTS)
• Atomic scale modeling (6 ECTS): molecular dynamics, Hartree-Fock modeling, and density functional theory (DFT).

• Thermodynamics and phase transitions
  • Phase transitions (3 ECTS)
  • Binary systems (3 ECTS)
• Dynamical properties of matter
  • Amorphous materials (3 ECTS)
  • Crystalline materials (3 ECTS)
• Defects and imperfections in solids (6 ECTS)

• Foreign language (French or English): 3 ECTS
• Scientific writing and communication: 3 ECTS
• Internship : 21 ECTS

Prussian Blue Analog nanocrystals are nano-objects at the frontier between molecules and bulk materials and have molecular properties that can be used for different applications such as gas storage materials for energy issues, magnetic properties for information storage, electrochemical and biosensors, catalysis, environmental purification, or biomedical applications. This work is  a study of the electron transport properties at the nanoscale of individual Prussian Blue Analog cubic nanocrystals. The conductivity values measured on individual nanocrystals are up to fifty times higher than those reported on PBA films.

Full publication : H. Therssen, L. Catala, S. Mazérat, T. Mallah, D. Vuillaume, T. Mélin & S. Lenfant. Electronic properties of single Prussian Blue Analog nanocrystals determined by conductive-AFM (2023) Nanoscale 15 19128-19138 [doi: 10.1039/d3nr04542k]

Drug solubility and bioavailability are the most important formulation challenges in pharmaceutical development, probably because a major part of the active pharmaceutical ingredients (APIs) are synthesized in the crystalline state which is often a poorly water-soluble state. Mesoporous silica carriers have recently gained interest in the pharmaceutical domain because of their potential to significantly increase the solubility of poorly water-soluble drugs, by adsorbing the active molecule in an amorphous and relatively stable state. This work shows that co-milling of porous SBA-15 matrix with the drug makes it possible the drug loading without significant damage for the structure of the matrix, enhancing thereby the capacity of loading to almost 40 wt%. It is shown that the physical state of ibuprofen (IBP) confined to silica carriers was amorphous between temperatures Tg and Tm of the bulk form of IBP.

Full publication : B. Malfait, N. Correia, A. Mussi, L. Paccou, Y. Guinet & A. Hédoux. Solid-state loading of organic molecular materials within mesoporous silica matrix: Application to ibuprofen (2019) Microporous and Mesoporous Materials 277 203-207 [doi: 10.1016/j.micromeso.2018.10.022]

Silicate glasses usually refer to amorphous materials in which SiO₂ forms a network of corner-sharing tetrahedra. These vitreous phases can further incorporate different cations leading to the well-known categories of borosilicate glasses, aluminosilicate glasses or soda-lime glasses. This paper reports an initial investigation of the rheology of Mg₂SiO₄ glass through classical molecular dynamics simulations. The goal of the present study is therefore to analyse the mechanical response and rheological behaviour of an olivine glass of forsterite composition Mg₂SiO₄ and to elucidate how local atomic rearrangements evolve in the deformation process at low temperature.

Full publication : V. Delbecq, P. Carrez & P. Cordier. Rheological properties of Mg₂SiO₄ glass: A molecular dynamics study (2023) Journal of Non-Crystalline Solids  619 122572 [doi: 10.1016/j.jnoncrysol.2023.122572]

The plastic deformation of materials comes from the ability of crystal lattices to shear through the movements of dislocations. The interactions of the different mechanisms of deformation are complex and depend on each other. Their understanding is necessary, and a precise observation of these phenomena must be performed in order to take them into account when building theoretical models at the microstructural scale. This study is dedicated to the determination of the best methodology to apply for the characterization of dislocation densities that can be used as input in micro-mechanical modellings.

Full publication : J. Gallet, M. Perez, R. Guillou, C. Ernould, C. Le Bourlot, C. Langlois, B. Beausir, E. Bouzy, T. Chaise & S. Cazottes. Experimental measurement of dislocation density in metallic materials: A quantitative comparison between measurements techniques (XRD, R-ECCI, HR-EBSD, TEM) (2023) Materials Characterization  199 112842 [doi: 10.1016/j.matchar.2023.112842]

Materials systems subjected to external forcing are often observed to self-organize into patterns. Instabilities arise in these systems that can trigger the formation of transient structures, which then evolve into metastable or even stable steady-state patterns. Such patterns have been reported in solids and alloys subjected to irradiation and to severe plastic deformation, resulting in microstructures with emergent pattern length scales and symmetry. Using a simple model for point defect and chemical transport in an irradiated alloy, along with phase field simulations, this work reports on a novel compositional patterning phenomenon at grain boundaries and show that it results from solute advection to grain boundaries coupled with anisotropic solute diffusion at grain boundaries.

Full publication : G. F. Bouobda Moladje, R. S. Averback, P. Bellon & L. Thuinet. Convection-Induced Compositional Patterning at Grain Boundaries in Irradiated Alloys (2023) Physical Review Letters  131 056201 [doi: 10.1103/physrevlett.131.056201]

Sensing with terahertz (THz) radiations (100 GHz−10 THz, λ: 3 mm−30 μm) has demonstrated valuable purposes, e.g., for the uncovering of hidden items or the detection of relevant chemical and biochemical compounds. These works investigated the near-field distribution associated to the photonic mode of terahertz photonic micro-resonators by scattering scanning near-field optical microscopy and propose a scenario based on the combination of the near-field with the far-field pattern of the probe/resonator ensemble that is in excellent agreement with the experimental data and propose an image analysis procedure to recover the near-field of such structures.

Full publication : L. Thomas, T. Hannotte, C. N. Santos, B. Walter, M. Lavancier, S. Eliet, M. Faucher, J.-F. Lampin & R. Peretti. Imaging of THz Photonic Modes by Scattering Scanning Near-Field Optical Microscopy (2022) ACS Applied Materials & Interfaces  14 32608-32617 [doi: 10.1021/acsami.2c01871]

The ability of complex parts production directly from a computer aided design without machining or assembling step has increased the interests in Additive Manufacturing. Laser powder bed fusion, largely employed for additive manufacturing, induces after each batch a large quantity of remaining powder. This study focuses on the possibility to reuse this remaining powder after a large number of production cycles and on the influence of such reusing on the microstructure and mechanical properties.

Full publication : E. Paccou, M. Mokhtari, C. Keller, J. Nguejio, W. Lefebvre, X. Sauvage, S. Boileau, P. Babillot, P. Bernard & E. Bauster. Investigations of powder reusing on microstructure and mechanical properties of Inconel 718 obtained by additive manufacturing (2021) Materials Science and Engineering: A  828 142113 [doi: 10.1016/j.msea.2021.142113]

Considering the exhaustion of petroleum resources and consumer request for sustainable products, starch is one of the most inexpensive and readily available bio-based polymer that has attracted a great deal of interest as potential alternative to conventional plastics for packaging applications. Here, the structure-property relationships of almost fully substituted fatty acid starch esters are investigated as a function of both fatty acid chain length and amylose/amylopectin ratio of the starch. The structural study has revealed a layered type organization in which starch chain planes are separated by fatty chains. The latter are interpenetrated and/or tilted for FASE-C16 whatever the origin of the starch is, and fatty chains partially crystallizes into a structure with hexagonal symmetry.

Full publication : A. Vanmarcke, L. Leroy, G. Stoclet, L. Duchatel-Crépy, J.-M. Lefebvre, N. Joly & V. Gaucher. Influence of fatty chain length and starch composition on structure and properties of fully substituted fatty acid starch esters (2017) Carbohydrate Polymers  164 249-257 [doi: 10.1016/j.carbpol.2017.02.013]

Chemical zoning in olivines is frequently found in unequilibrated chondrites, both in carbonaceous chondrites and ordinary chondrites meteorites. This work uses analytical transmission electron microscopy to study the microstructure of the fayalite-rich matrix grains and interfaces with forsterite fragments within samples of the Allende meteorite. The analyses suggest that the composition profiles were formed by solid-state diffusion during the thermal metamorphism episode. Time–temperature couples associated with the diffusion process during thermal metamorphism are deduced from profile modeling. Considering the uncertainties on the diffusion coefficient value, the work shows that the peak temperature experienced by the Allende meteorite is ranging from 425 to 505 °C.

Full publication : P. Cuvillier, H. Leroux, D. Jacob & P. Hirel. Fe‐Mg interdiffusion profiles in rimmed forsterite grains in the Allende matrix: Time–temperature constraints for the parent body metamorphism (2015) Meteoritics & Planetary Science  50 1529-1545 [doi: 10.1111/maps.12493]

Mantle convection is elusive at human timescale since it operates over hundreds of million years. Seismic anisotropy, which samples the direction-dependence of elastic wave propagation, represents one of the potential observables of past convection since it is an indicator of flow patterns in the deep Earth through the development of crystal preferred orientations. This work aims to determine the efficiency of dislocation glide in the pure MgSiO₃ end-member bridgmanite at conditions relevant to the lower mantle by relying on atomic scale calculations to model dislocation glide at high-pressure and temperature. The work shows that in the lower mantle, bridgmanite would always be in the thermally activated regime and that stresses close to 1 GPa are still necessary to move dislocations in bridgmanite. In the uppermost lower mantle, dislocation glide is inhibited and other deformation mechanisms, involving diffusion, are needed.

Full publication : A. Kraych, P. Carrez & P. Cordier. On dislocation glide in MgSiO 3 bridgmanite at high-pressure and high-temperature (2016) Earth Planet. Sci. Lett.  452 60-68 [doi: 10.1016/j.epsl.2016.07.035]