Séminaire d'Institut

Mardi 12 Mai 2026 à 10h30.

General talk: Stressing soft solids: from the microscopic dynamics to the mechanical behavior

Luca Cipeletti
(Laboratoire Charles Coulomb, Montpellier)

Salle de convivialité (1ère partie, 10h30 - 11h30) puis Salle de Séminaires Lippmann (11h30 - 12h)

Invité(e) par
Christophe Ybert

présentera en 2 heures :

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General talk: Stressing soft solids: from the microscopic dynamics to the mechanical behavior

Dynamic light scattering (DLS) is a standard technique to investigate the (average) microscopic motion of stationary, equilibrated soft systems as, e.g., in the particle sizing of Brownian particles. I'll show a few examples of how DLS can be hijacked to investigate the non-uniform, time-varying dynamics of out-of-equilibrium soft solids under an external drive, aiming at unveiling the microscopic origin of their mechanical behavior beyond the linear regime.

More specialized talk: Microscopic origin of the toughness of multiple polymer networks

Multiple polymer networks are soft solids with outstanding mechanical properties, combining large extensibility, and high stress at rupture, thanks to delocalized damage. In spite of their importance in many applications, the microscopic mechanisms ruling their mechanical behavior are still poorly understood. We directly address this knowledge gap by investigating when and where bonds break before and during material failure, both experimentally and numerically [1]. We reveal that their remarkable resilience stems from damage delocalization, where microscopic relaxation dynamics redistribute stress over a previously unsuspected, extended volume, thereby protecting the material from the growth of catastrophic cracks.

[1] N. Orr et al., PNAS 123, e2530175123 (2026)

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