Seminars

Jeudi 20 novembre 2025 - Amphi Charpak

Engineering Plant-based Food Emulsions and Foams: Mayo to Milk
Vivek Sharma
Chemical Engineering, University of Illinois Chicago, IL.

The success and suitability of plant-based emulsions as sustainable, palatable, and healthy substitutes are tied to their ability to emulate the properties, processing, and functionalities of animal-based products. We translate several challenges underlying the design, manufacturing, and consumption of plant-based emulsions into fundamental quests in soft matter physics and rheology. We characterize the ingredient-dependent differences in flow behavior of animal and plant-based emulsions, with milk representing dilute and mayo jammed-dense emulsions, respectively. The presence of macromolecular additives like polysaccharides and proteins in suspending fluid and interfaces of plant-based emulsions makes their response non-Newtonian. The extensional and interfacial flows influence the emulsification, emulsion stability, and shear rheology. At the macroscale level, the extensional rheology response of the emulsions impacts many processing operations and sensory perception of texture, mouthfeel, and apparent thickness, stretchiness, or stringiness. However, there is a clear lack of appropriate extensional rheology characterization techniques, and a limited understanding of macromolecular or drop/particle microphysics that sets the rheological response and processability. We develop experimental protocols for characterizing the influence of ingredients like proteins and polysaccharides on shear rheology and extensionally dominated interfacial flows in pinching necks and draining films. By visualizing and analyzing flows in pinching necks created using dripping, dipping, dripping-onto-substrate (DoS) rheometry, and stretching bridges like in the tack test, we characterize the extensional rheology response relevant for processing and applications. We show that a deeper understanding of ingredient- dependent emulsion rheology, shelf-life, and consumer perception involves a joyous odyssey into the physics and mathematics of self-similarity, finite-time singularity in free-surface flows, colloidal interactions, coalescence and lubrication flows, pinching and spreading kinetics, stretched polymer physics, protein science, and scaling theory or dimensional analysis.

Jeudi 6 novembre 2025

Polymer Colloids: From Synthesis to Functional Properties
Elise Deniau
IMMM, Le Mans Université

The work presented adresses the field of materials chemistry and physicochemistry, with particular emphasis on the design, characterization and valorization of functional colloids structured at the nanometric scale.
Through an interdisciplinary approach combining controlled polymer syntheses, physical chemistry of interfaces and multi-scale characterizations, this research has led to a better understanding of structure-property-function relationships in a variety of application contexts, such as gas or micropollutant capture, organic electronics, active ingredient release or micro- and nano-plastic degradation.
All this work illustrates the originality of the properties of colloidal systems, while highlighting the potential for innovation offered by mastery of macromolecular architectures. These advances open up promising prospects for the design of new nanomaterials to meet today’s major societal challenges, notably by providing solutions to major environmental issues such as climate change, water pollution and plastic pollution.