Polysaccharide-based microgels by reactive extrusion: Synthesis, structure, and properties

            In cosmetic formulations, the use of bio-based and biodegradable components has become a major challenge, with ambitious goals such as 98% biodegradability set by industry players. However, natural polymers currently present limitations in terms of molar mass and macromolecular architecture, requiring high mass fractions to achieve texturizing properties comparable to fossil-based microgels such as Carbomers. Polysaccharide-based microgels, while promising due to their biodegradability and rheological properties, are currently produced through multi-step and complex processes, which is unsuitable for large-scale production.

In this context, this thesis project aims to explore several macromolecular engineering strategies to develop bio-based and biodegradable microgels using an innovative process, reactive extrusion, and to characterize their rheological and structural properties. To increase the molar mass by branching polysaccharides (alginate, chitosan, hyaluronic acid), a straightforward, efficient, and by-product-free chemistry will be implemented, coupled with controlled flows. Specifically, two complementary strategies, called “Bottom-up” and “Top-down”, will address several fundamental questions. This experimental work will focus on understanding the effect of these strategies on the structure, rheological properties, biodegradability of the microgels, and the underlying physics. In fine, these results will open new perspectives for producing polysaccharide-based microgels via a robust and sustainable process.

            This project will be integrated within the laboratory IMP (Université Jean Monnet). The IMP team is renowned for his research activities in polymer science, with important facilities. Its main research aim is to establish and to control relationships between chemistry, structure, rheology, and processing.

The Polymer Materials Engineering Laboratory (Ingénierie des Matériaux Polymères, IMP, UMR CNRS 5223) is a mixed research unit involving the CNRS and three higher education and research institutions: the Lyon INSA, Claude Bernard Lyon 1 University and Jean Monnet Saint-Etienne University. The IMP laboratory brings together nearly 200 people, including 83 permanent staff and more than 110 doctoral and post-doctoral students. The Laboratory has a unique set of skills covering the entire value chain in the field of polymer materials. The strength of the IMP lies in its ability to coordinate scientific knowledge and the means to implement a multi-scale and multi-disciplinary engineering approach by assembling fundamental building blocks from the chemistry and physics of polymers involved in implementation processes in the laboratory, but also at the pilot scale to design polymer materials with a controlled architecture, respectful of the environment and with functionalities.

Highly motivated students with a Master/Ingénieur degree, or equivalent, in the field of polymer or colloids science (physical-chemistry) are encouraged to apply. A prior knowledge on polysaccharides, rheology or extrusion will be also appreciated. Excellent writing and oral communication skills.