The MEGALIT project has the objective to explore the potential to enhance functionalities of near-surface Metal Glasses (MG) recognized for their outstanding mechanical properties (Metal-like) and surface state (Glass-like), in order to substitute complex existing solutions by a single-multifunctional material coating approach. Our strategy relies on the advantages that can provide the combination of Physical Vapor Deposition coating technology suitable for the deposition of thin films of MG which show better ductility than bulk material and ultra-short pulsed laser irradiation treatment enabling an improvement of some of the required properties at the near-surface of the materials. The industrial relevance of bulk metallic glasses still suffers from detrimental weaknesses (such as insufficient toughness, limited industrial scale-up of the processing technologies and prohibitive cost) for large scale applications. However, these drawbacks can be reduced by decreasing their dimensionality, as in thin films elaboration. Within the MEGALIT project, the detailed strategy to address this challenge is to (i) carefully design the chemical composition of the amorphous alloys with regard to the targeted application ; (ii) exploit thin films PVD coatings technologies which are particularly adapted to generate amorphous metastable phase ; and (iii) tailor the functionalization of the coating surface with adequate ultrafast laser irradiation treatment. Such an advanced process could provide two distinct modifications of the surface and near-surface characteristics of the coating (depending on the irradiation conditions): a modification of the surface state (topography and roughness), to adapt the wetting properties (while maintaining the coating amorphous structure), or a controlled phase transition of the film to form a kind of composite-like nanostructure. Such design of metallic glass composites is a recent trend in the field of metallic glasses where breakthrough performances in terms of mechanical properties (toughness beyond that of the best existing alloys) have been demonstrated. This project is based on the knowledge of the IJL and MATEIS laboratories and IREIS, specialists of amorphous metallic alloys in thin film, of the Hubert Curien laboratory, specialist of the surface functionalization using laser and of the industrial partner (IREIS - HEF group), specialist of the industrial coatings and laser surface texturation at industrial scale. The outcome of this project will deliver technological solutions in three application fields: - Bio-medical applications in order to design a competitive antibacterial and hydrophobic surface treatment ensuring complementary corrosion and abrasion-resistant functions. - Aeronautics, energy and chemical industries to increase the erosion resistance of substrates (to sand, water, dust and potentially reactive particles) in severe operating conditions by combining enhanced mechanical properties (toughness, rigidity, hardness, fatigue resistance) and chemical stability. - Energy storage technologies and process industries, addressing the technical issue of the protection of components operating in corrosive conditions and requiring also electrical conductivity as well as mechanical strength. Consequently, the aim of the project relies on the demonstration of the potential of key enabling technologies (photonics and advanced materials) to address multifunctional-by-design issue, rather than a single property, which will make thin films metallic glasses distinctively attractive. While strong scientific and technical impacts are expected from this multidisciplinary approach, the partners are in position to further exploit positively the MEGALIT project results toward the socio-economical world.

The aim of the present collaborative research project is to investigate and develop novel Ti-based metallic glasses with surface modifications for dental applications. These shall combine biocompatibility, bio-corrosive resistance, good mechanical properties and particularly thermoplastic formability in the SCLR in order to achieve antimicrobial and/or tissue-integrative properties. In order to achieve this goal four main scientific milestones are targeted: 1) Developing a novel Ti-based biocompatible MG with enhanced (micro)patterning kinetics via optimizing the formability parameter S. 2) Development of appropriate routes to achieve low density, low elastic modulus and high Poisson’s ratio which functions as an excellent stress-shielding material in daily use. 3) Production and tuning of surface patterns (threads or anchoring sites) with improved antimicrobial/osseointegrative properties. 4) Investigation and understanding the mechanisms of cell adhesion, bactericidal adhesion and biocorrosion. The final target of this project is to develop a biocompatible Ti-based metallic glass implant with modulated topography which can promote the cellular response from initial attachment and migration to differentiation and production of new tissue without the need of exogenous growth factors. Together with the lowered cost by the addition of metalloids/abundant metals which in turn increases the glass forming ability, these cutting edge advanced alloys can open a new avenue for tough and bioresistant implants which do not cause antibiofouling, and assist the selective growth of dental pulp stem and epithelial cells.

Strain-induced crystallisation (SIC) in natural rubber is at the origin of its outstanding performances such as self-reinforcement and resistance to failure. The SICX project has several objectives: First, it aims to provide a comprehensive set of data describing the kinetic evolution of the microstructure associated with SIC and its impact on the macroscopic mechanical properties, specifically self-reinforcement, which are both not yet decrypted. Secondly, these data will enable developing 3D modelling based on identified physical mechanisms and suitable for being implemented in a FEM code. Thirdly, ageing in complex thermomechanical environments, under air and solvent exposure, and its interactions with SIC, will be studied experimentally and finally modelled. Identifying the main physical ageing mechanisms in real-life conditions is a major scientific challenge as it is essential to extend the life of key industrial materials. To this aim, the SICX project will combine advanced physical characterisation by real-time X-ray diffraction during tensile tests, by electron microscopy and by NMR (France), ageing tests in well-controlled operating conditions and advanced thermomechanical 3D modelling (Germany). All partners have many years of experience in their respective fields and will combine their approaches from polymer physics and material modelling.

Predicting both climate and temperature evolution requires, among other parameters, to quantify properly the contribution of clouds through a better understanding of their formation. Clouds form by condensation of water vapor on particles (aerosols) of varying morphology and chemical composition and with sizes down to a sub-micron level. WATEM will study the early stages of this process in situ in a Transmission Electron Microscope (TEM). Providing the required spatial resolution, the TEM also brings morphological (2D/3D), structural and chemical information. The challenge to control thermodynamic conditions for condensation of liquid droplets from a humid gaseous environment will be taken up in a dedicated Environmental TEM (ETEM) working at a variable partial pressure (< 20 mbar as in ESEM: Environmental Scanning EM). We will develop a tip for a sample holder based on a Peltier cooled micro-device allowing observing solid, liquid and vapor phases at the same time, and evolution at their interfaces, as well as pure liquid without sealing membranes. Based on this technological development, WATEM will highlight the scientific expertise of three teams whose expertise are both complementary and with sufficient overlap so that effective communication and exchanges can take place together with effective intra- and inter-team work thus providing a solid basis for the success of the project: IRCELYON (atmospheric chemistry, liquid/gas ETEM, liquid/gas ESEM), MATEIS (liquid/gas ETEM, liquid/gas ESEM, electronic tomography, specific sample holders), MAJULAB (micro/nano devices, specific sample holders, ESEM/ETEM). WATEM will revolve around 5 scientific/technological WP (in addition to the WP concerning the project management). WP1 concerns the realization of the Peltier cooled micro-device adaptable both to an ESEM and to an existing sample holder in an ETEM. This original solution will be completed by other existing alternatives a priori less effective from the point of view of fine control of the temperature, and therefore of the conditions of condensation of water on the aerosols. These alternatives allow nevertheless to manageable the risk of delay in the development of our prototype. In WP3, WP4 and WP5 particular attention will be given to the effects of irradiation so as to minimize their effect on the observed phenomena and to develop relevant experiment protocols. WP3 will validate and calibrate the Peltier micro-device in the ESEM by studying the water condensation on large collections of model artificial aerosols (statistical studies) thus taking advantage of the space existing in the ESEM chamber and in order to facilitate the experiments to be carried out in the ETEM; tomography approaches in ESEM, under condensation conditions, will also be tested. A similar approach in ETEM will be performed in WP4, taking advantage of the results acquired in WP3: validation of the Peltier micro-device in ETEM on the same model aerosols and measurements of the deliquescence (DRH) and efflorescence (ERH) relative humidity. We will also study the role of the mixed nature of aerosols (for instance: inorganic/organic) on hygroscopicity using analytical methods (EDX/EELS), complementary to imaging, as well as electronic tomography. Finally, in WP5 we will tackle the study of natural aerosols (atmospheric sampling) in ETEM; here the main challenge will be to be able to follow in real-time the evolution of the solid/liquid and liquid/vapor interfaces essential for an understanding of the growth phenomena of water nanodroplets and their implication in cloud formation. The successful development of the approach an strategy proposed in WATEM will allow extension to studies in other fields: suspension of nano-objects in liquid, crystallogenesis in nano-confined media, evolution of biological sub-micron systems, …

The electroluminescence of solids is the realm of semiconductors and related organic materials. In 2019, we discovered that a graphene transistor encapsulated in hexagonal Boron Nitride and submitted to a large bias becomes electroluminescent in the mid-infrared. This device operates in the open air and might be a breakthrough technology in the domain of mid-infrared source. Indeed, compact and cheap sources are inefficient and slow in this optical domain which is of considerable interest for free space telecommunication and pollutant detection. The triple challenge taken by the ELuSeM consortium is to strengthen the understanding of basic mechanisms leading to HPhP electroluminescence, optimize geometry and harness far-field coupling with nano-antennas to extract a significant fraction (few %) of the electrical power budget, investigate new low-cost routes for large scale hBN production.