Michel Cloitre

CNRS/ESPCI Paris

Physicist and Chemical Engineer

Fellow, Elected 2024

Michel Cloitre is a Research Director at the Centre National de la Recherche Scientifique (CNRS) in France. He received his PhD in physics from Pierre and Marie Curie University in Paris, in 1989. He then joined Orsay University to establish a group working on the fluid dynamics of complex fluids (1991), and later moved to join a new research unit between CNRS and ATOCHEM, now Arkema (1996‐2003). Currently, he is a member of the Molecular, Macromolecular Chemistry and Materials Laboratory of ESPCI in Paris, which he directed in the last 6 years.

Michel is an international authority in the rheology of jammed soft colloidal suspensions. His rigorous and thoughtful work has established a link between the internal microstructure of the soft particles and their rheological properties. His scholar approach to science and attention to detail (by working closely with chemists and often designing the desired materials for a planned rheological investigation) has established a ‘rheological school of thought’ regarding the investigations of pasty materials and the design of formulations. His meticulous studies with wellcharacterized materials have opened new directions for understanding the effects of flow on the structure and macroscopic behavior of soft colloidal glasses, pastes and emulsions, gels, associating polymers and vitrimers. They have also led to major innovations in the industry, in particular to the development of successful new product lines associated with rheology modifiers and liquid‐liquid encapsulation.

Michel is a very talented experimentalist with an extraordinary deep grasp of soft matter theory. He is using a variety of experimental techniques, often in combination (for example, rheomicroscopy), and has developed several experimental tools (for example, fluorescent particle tracking velocimetry) and protocols (rejuvenation and control of structural memory) to address formidable challenges regarding the role of the microstructural characteristics of soft particles on their nonlinear rheological response, yielding, wall-slip and flow. To deeply understand the rheology-microstructure link, Michel has used particle simulations and modeling, often in the context of prolific collaborations. A key outcome is the development of the elastohydrodynamic model that has established the mechanism to understand and tailor the wall slip, shear thinning and normal stresses of jammed soft particle suspensions and emulsions. Other outstanding accomplishments include the scaling of rheological aging, the detection, explanation, control and elimination of internal stresses, and the link between local (velocity profiles) and global rheology to microstructure in the context of wall-slip, shear thinning and yielding of pasty microgel suspensions, and finally, establishing rheological approaches to compare and distinguish the softness of colloidal particles and exploit their consequences on the rheology of jammed suspensions.