ED Sciences Chimiques
Manufacturing of polymer composites by soft 3D printing
by Alexie MATTEI (Laboratoire du Futur)
The defense will take place at 14h00 - Amphithéâtre 1 ENSMAC 16 avenue Pey Berland, 33600 PESSAC
in front of the jury composed of
- Jacques LENG - Directeur de recherche - Université de Bordeaux - Directeur de these
- Anniina SALONEN - Professeure - ESPCI, SIMM - Rapporteur
- Christophe MARQUETTE - Directeur de recherche - ICMBS - Rapporteur
- Philippe POULIN - Directeur de recherche - CRPP - Examinateur
This thesis investigates the processing of thermoplastic polymer powders by direct ink writing, a versatile additive manufacturing technique suitable for a wide range of materials. The process involves extruding a fluid or soft solid—the ink—which must retain the deposited geometry without deformation or collapse of the 3D structure. To meet this requirement, inks were formulated with Carbopol, a polyacrylic acid that imparts yield-stress behaviour: in the absence of applied stress the ink behaves like a solid, and flow occurs only once a critical yield point is exceeded. The selection of Carbopol grade is of particular importance, as it governs the physical properties of the ink and its sensitivity to mechanical and chemical degradation. The grades were therefore characterised in advance to identify the one offering the most reliable control during printing. Direct ink writing was examined in two complementary configurations: freeform and confined. In freeform printing, deposit height is unconstrained; the approach is simple to implement but filament morphologies are highly sensitive to experimental conditions. In confined printing, the extrusion head sets the layer thickness; deposition requires greater care but allows improved control of the final architecture. We investigate the relationship between process parameters and filament morphology across both configurations, while identifying the resolution limits of each method. Finally, by working with inks of different properties, this study establishes a foundation for multi-material printing, with the potential to incorporate functional fillers.
Developing new oxides as stable and performant oxygen electrodes for high temperature water electrolysis devices
by Romuald FRUGIER (ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux)
The defense will take place at h00 - Amphithéâtre ICMCB, 87 Avenue du Dr Albert Schweitzer, 33600 Pessac, France
in front of the jury composed of
- Jean-Marc BASSAT - Directeur de recherche - Université de Bordeaux - Directeur de these
- Julie MOUGIN - Directrice de recherche - CEA - Liten - Rapporteur
- Miguel LAGUNA-BERCERO - Tenure Scientist - Universidad de Zaragoza - Rapporteur
- Jacinthe GAMON - Chargée de recherche - Université de Bordeaux - CoDirecteur de these
- Monica BURRIEL - Directrice de recherche - Université Grenoble Alpes - Examinateur
- Cyril AYMONIER - Directeur de recherche - Université de Bordeaux - Examinateur
- Julien VULLIET - Ingénieur de recherche - CEA - Le Ripault - Examinateur
- Patrice TOCHON - Cadre scientifique - Genvia - Examinateur
Dihydrogen, more commonly called hydrogen, is employed as chemical reactant in several industrial sectors. Water electrolysis is a way to produce low-carbon hydrogen, generally labelled green hydrogen. However, this technology is non-mature and highly expensive. When operating at high temperature (700-800°C), water electrolysis offers a high efficiency, however the main challenge is to limit the electrochemical cells degradation, particularly the reactivity between the components. In the past, several studies were conducted at the ICMCB on oxygen electrode materials, particularly the Ruddlesden-Popper (RP) type nickelates. Pr4Ni3O10±δ, PrNiO3-δ and La1.5Pr0.5NiO4±δ were identified as very promising compounds for this application. These were studied through this Ph.D. thesis alongside with the RP nickelates n = 2 La3-xPrxNi2O7±δ which were not reported in the literature to the best of our knowledge (excepted La3Ni2O7±δ). The oxides synthesis and their structural characterisation were performed, as well as the study of their stability, either alone or in the presence of the barrier layer (located between the electrode and the electrolyte layers) materials. Symmetrical cells were prepared to characterize the oxygen electrode electrochemical performances. Two sintering routes were investigated: a co-sintering of the electrode and GDC and a conventional 2-steps sintering. The electrodes sintering was thoroughly studied, leading to optimized thicknesses. A study in complete cells configuration allows to extract the initial and long-term electrochemical performances in SOEC mode. Post-mortem investigations were conducted using XRD and SEM-EDX. Finally, Ce0.7Pr0.3O2-δ was studied as an alternative barrier layer material. Being a mixed ionic and electronic conductor under pO2 ~ 0.2 it is known to improve the performances through an improved interface and new reactive pathways.
ED Sociétés, Politique, Santé Publique
Urban environments and nature: understanding the conditions that support children's play and well-being
by Louise WALLERICH (Bordeaux Population Health Research Center)
The defense will take place at 15h00 - Amphi Duguit Université de Bordeaux - Campus Bordeaux Pey-Berland 35 Pl. Pey Berland, 33000 Bordeaux
in front of the jury composed of
- Catherine BOUVE - Maîtresse de conférences - Université Sorbonne Paris Nord - Examinateur
- Thierno DIALLO - Professeur agrégé - Université Laval - Rapporteur
- Anne ROUé LE GALL - Enseignant-Chercheur (ENAC, ISAE) - Université Rennes, EHESP - Examinateur
- Yan KESTENS - Professeur - École de santé publique de l'Université de Montréal - Rapporteur
Children's health is deeply influenced by their living environment. In urban settings, dynamics such as densification, the scarcity of natural spaces, and territorial inequalities make it more difficult to access environments conducive to their overall development. This thesis, situated within the framework of population health intervention research (PHIR), aims to better understand the environmental and social conditions that promote children's well-being, particularly through the lens of play and access to nature in cities. The research approach is structured into four main steps. First, a review of the scientific literature identifies five major categories of environmental determinants of children's health: urban planning, contaminants, parental environment, social conditions, and climate change. These determinants interactively influence children's physical, mental, and social health.Second, a focused literature review examines urban planning strategies that benefit children, highlighting five key neighborhood attributes: street design, home-to-school routes, play areas, access to nature, and housing quality. Building on these findings, the thesis explores more specifically the greening of urban spaces as a lever to encourage free play and well-being. A qualitative study, conducted with urban planning and early childhood professionals, identifies the mechanisms through which urban nature supports natural play. It highlights the importance of discreet adult presence, the diversity of natural elements, collective “permission zones,” and cross-cutting public policies. A conceptual model is developed to formalize these enabling conditions. Finally, the thesis offers an empirical test of this model through the APPIE-GREEN case study, which examines the greening of two schoolyards in Bordeaux as part of the "Cours Buissonnières" program. This study identified several structural barriers to the emergence of free play. Despite the apparent diversity of developments, space remains highly regulated: green areas are often linked to specific, supervised functions, limiting spontaneous appropriation by children. While children develop creative coping strategies, these practices are rarely encouraged as they are perceived as transgressive. These findings nuance the initial model by emphasizing the importance of institutional variables (rules, school time, educational posture) and social representations that shape the actual playability of spaces. The general discussion explores the scope, limitations, and transferability of these results, repositioning the reflection within current public health and urban planning challenges. It underscores the need for intersectoral policies that are sensitive to local dynamics and guided by the real needs of children. This work advocates for an ecosystemic, integrated, and democratic approach to urban development, where children are no longer merely passive users but legitimate actors of public space. This thesis thus proposes a framework for analysis and action to rethink urban environments from a child-centered perspective and to help reduce social health inequalities from an early age. It opens the way for future research on the evaluation of urban transformations, child participation, and the construction of truly child-friendly territories.