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Synthesizing and Understanding Polymer Networks containing Tethered Weak Bonds by Charlène Breton -
Vendredi 25 septembre 2026 à 10h30 - Auditoire LAVO51 - Bâtiment Lavoisier - Place Louis Pasteur, 1 - 1348 Louvain-la-Neuve -
Soft matters such as elastomers and gels are widely used in our daily lives. However, elastomers often face a tradeoff between toughness and stiffness, while gels are generally weak and brittle. Inspired by biological materials, the concepts of sacrificial bond and hidden length have been explored as a toughening mechanism of soft matter. Sacrificial bonds are weak bonds that rupture before strong bond failure, enabling molecular unfolding and thus releasing a hidden length. Although this concept has been incorporated in various artificial polymer networks, there is still a lack of mechanistic and quantitative understanding of materials containing sacrificial bonds. Therefore, this thesis aims to address this issue by developing a rational framework to quantitatively understand the influence of sacrificial bonds and hidden length on macroscopic properties. First, a tethered weak bond was synthesized to develop a well-defined model system in which both sacrificial bond strength and hidden length can easily be tuned. The weak bond is based on the formation of terpyridine bis-complexation with various transition metal. A model tetraPEG-based network was first investigated in the gel state. The influence of the sacrificial bond was then studied in randomly crosslinked elastomers. Characterization across different length scales, from a molecular point of view to the macroscopic properties, have been performed to understand the interplay of sacrificial bond strength, hidden length and network topology.
Jury members :
Prof. Charles-André Fustin (UCLouvain) (Supervisor)
Prof. Evelyne Van Ruymbeke (UCLouvain) (Chairperson)
Prof. Jean-François Gohy (UCLouvain) (Secretary)
Prof. Costantino Creton (ESPCI Paris – PSL University, France)
Dr. Mostafa Ahmadi (Johannes Gutenberg University, Germany)
Pay attention : the public defense of Charlène Breton will also take place in the form of a videoconference
