ED Sciences Chimiques
Synthesis of clickable organic photochromes for their grafting on self-assembled monolayers
by Chloé COURDURIÉ (Institut des Sciences Moléculaires)
The defense will take place at 14h00 - Salle de Conférence - 3ème Est Université de Bordeaux Institut des Sciences Moléculaires (UMR-5255) - Bâtiment A12 351 Cours de la Libération 33405 Talence
in front of the jury composed of
- Luc VELLUTINI - Professeur des universités - Université de Bordeaux - Directeur de these
- Émilie GENIN - Professeure des universités - Université de Bordeaux - Directeur de these
- Rémi METIVIER - Directeur de recherche - École Normale Supérieure Paris-Saclay - Rapporteur
- Eléna ISHOW - Professeure des universités - Université de Nantes - Rapporteur
- Isabelle GOSSE - Professeure des universités - ENSMAC - Bordeaux INP - Examinateur
- Jean-Louis BANTIGNIES - Professeur des universités - Université de Montpellier - Examinateur
Photo-switchable compounds, whose structure and properties change reversibly under light irradiation, give rise to numerous applications: for optical products (variable tint lenses), in biology or for data storage (rewritable optical memories). The design of responsive materials allowing high-density optical data storage with a maximal fatigue resistance is one of the greatest challenges in this last field. In this context, the project aims at designing photosensitive self-assembled monolayers (SAMs) based on photoresponsive switches in order to confer high spatial resolution to the storage devices. Non-linear optic (NLO) in particular Second Harmonic Generation (SHG) will give non-destructive readout ability. Photochromes from two families, azobenzenes and DASAs (Donor-Acceptor Stenhouse Adducts), were synthesized and characterized in linear and non-linear optics. The orthogonal photoswitching behavior of both families has been also studied. A terminal alkyne was added on photochromes to allow their covalent grafting onto a monolayer terminated by an azide function via a click reaction. The conditions of this copper-catalysed azide-alkyne cycloaddition (CuAAC) were optimized for each type of photochrome. These photoresponsive SAMs have been characterized by goniometry, PM-IRRAS, AFM, ToF-SIMS, VisRAS and R-SHG. This work paves the way to the development of SAMs mixing two types of photochromes which can be independently controlled and so addressing the challenge of molecular multi-encoding.
Dynamic behavior of light-responsive coacervates in microfluidic droplets
by Zi LIN (Centre de Recherche Paul Pascal)
The defense will take place at 10h00 - Amphitheatre Centre de Recherche Paul Pascal, 115 Avenue Schweitzer 33600, Pessac
in front of the jury composed of
- Jean-Christophe BARET - Professeur des universités - Centre de Recherche Paul Pascal - Directeur de these
- Lea-Laetitia PONTANI - Chargée de recherche - Laboratoire Jean Perrin, UMR 8237 - Examinateur
- Olivier MONDAIN-MONVAL - Professeur des universités - Centre de Recherche Paul Pascal - Examinateur
- Zoher GUEROUI - Directeur de recherche - Ecole Normale Supérieure - Rapporteur
- Fouzia BOULMEDAIS - Directrice de recherche - Institut Charles Sadron - Rapporteur
Living cells are dynamic compartmentalized systems that operate under non-equilibrium conditions. Emulating such dynamic compartmentalization in artificial systems is gaining attention in soft matter and bottom-up synthetic biology. Liquid-liquid phase separation (LLPS) is particularly key to produce dynamic compartments in biology. This phenomenon underlies the formation of biomolecular condensates in cells and has been hypothesized to play a role in the emergence of protocells at the origins of Life. In vitro, coacervate microdroplets assembled from oppositely charged polyions in water are used to emulate these bio-inspired LLPS processes. Coacervation has been extensively studied at thermodynamic equilibrium, but experimental investigations of dynamic coacervates remain scarce. Given its spatiotemporal resolution, light is particularly interesting to trigger dynamic behaviors in coacervate droplets. The recent design of light-responsive coacervates based on azobenzene photoswitches has opened avenues for dynamically controlling the dissolution and formation of coacervates with light. The dynamics of these processes are yet poorly understood. The main objective of this thesis is to investigate the dynamics of light-actuated DNA/azobenzene coacervate decay, growth and deformations using droplet-based microfluidics. After characterizing the azobenzene photoisomerisation kinetics, we produce photoswitchable coacervates within water-in-oil droplets using microfluidics. We study the relationship between coacervate size, azobenzene concentration and isomerization to build the phase diagram of DNA/azobenzene coacervation. We then investigate the kinetics of coacervate dissolution and reformation under UV and visible light, respectively, at varying coacervate sizes and light intensities to decipher the mechanism of the two processes. Ultimately, we demonstrate complex non-equilibrium coacervate deformations under optimal co-illumination conditions.
Macromolecular engineering of electroactive fluoropolymers: towards adjustable functional properties
by Raymond KHAYAT (Laboratoire de Chimie des Polymères Organiques)
The defense will take place at 9h00 - IECB - Amphithéâtre Auditorium IECB, 2 Rue Robert Escarpit, 33600, Pessac
in front of the jury composed of
- Guillaume FLEURY - Professeur - Université de Bordeaux - Directeur de these
- Emmanuel DEFAY - Head of Unit Nanotechnology - LIST - Rapporteur
- Simon HARRISSON - Directeur de recherche - LCPO-CNRS - Examinateur
- Bruno AMEDURI - Directeur de recherche - ICG-CNRS - Rapporteur
- Ilias ILIOPOULOS - Directeur de recherche - ENSAM-CNRS - Examinateur
Co- and ter-polymers based on vinylidene fluoride have gained increasing attention in recent years owing to their unique combination of high electroactivity and excellent mechanical and chemical properties. Further advance in the design of these remarkable materials, and in particular for the relaxor-type P(VDF-TrFE-CTFE), is foreseen by an enhanced control of their macromolecular architecture. In this work, two strategies were investigated to enhance the functional properties of P(VDF-TrFE-CTFE). Firstly, an extended control of monomer sequencing during polymerization was pursued in order to improve the polymer homogeneity and final electroactive properties. To achieve this, the monomer reactivity ratios for VDF, TrFE, and CTFE terpolymerization were determined using diverse methodologies, including binary and ternary system approaches. These ratios were then implemented in a theoretical treatment to simulate the polymerization reaction. Utilizing this model, various parameters, including the monomer feeding rates, were optimized to achieve precise control over polymerization, resulting in polymers with narrower composition distributions. This refinement in composition homogeneity led to optimized polymer properties, including increased crystallinity, higher dielectric constant, and a more pronounced relaxor ferroelectric behavior. Secondly, a chemical post-modification strategy was employed to improve the dielectric behavior of P(VDF-TrFE-CTFE). This approach involved a two-step functionalization process. The initial step introduced double bonds on the polymer backbone using a base, such as ethylene diamine, following a dehydrochlorination mechanism. Subsequently, the formed "double bond" platform served as a site for precise post-modification of the P(VDF-TrFE-CTFE) architecture. A successful modification involved the reaction of the double bonds with mCPBA following an epoxidation reaction. This approach resulted in a significant improvement in dielectric properties, manifesting as higher relative permittivity, increased maximum polarization, and reduced remanent polarization.
ED Droit
The minor's participation in his/her own protection - French-Quebec comparative law
by Amira MAAMERI (CENTRE EUROPÉEN DE RECHERCHES EN DROIT DES FAMILLES, DES ASSURANCES, DES PERSONNES ET DE LA SANTÉ)
The defense will take place at 14h30 - Salle des thèses Université de Bordeaux 16 avenue Léon Duguit 33600 Pessac
in front of the jury composed of
- Vicky LAFANTAISIE - Professeure - Département de psychoéducation et de psychologie de l'Université du Québec en Outaouais - Rapporteur
- Mostefa MAOUENE - Professeur - Faculté de droit et de sciences politiques de l'Université Djillali de Sidi Bel Abbès - Rapporteur
- Véronique ROUYER - Professeure - Faculté de psychologie à l'Université de Bordeaux - Examinateur
- Emmanuelle BERNHEIM - Professeure - Faculté de droit de l'Université d'Ottawa - Examinateur
As regards child protection, speech of participation of the minor in his own protection is to consider this one like a subject of active right and not only like one object of protection. In this direction, the International Convention of the Children's rights affirmed the capacity of the child to be taken part in his own protection, guaranteed by its right to the expression. Consequently, the child to be protected is not simply any more perceived like a vulnerable human being requiring a State aid (passive subject of right), before the placement, during and after this one. The minor is recognized as a citizen in becoming ( active subject of right) to which a series of rights are conferred such as the right to take part in the decisions which relate to it according to its age and its degree of understanding, the right to freedom to think, of conscience and religion or the right to reach information diversified and aiming at promoting its wellness physics, mental and social. Accordingly, it is by the means of the exercise of its rights that the protected child can become the actor of his own protection.