Elastic Instabilities in Soft Matter: From Squeaking Interfaces to programmable fluids - Adel Djellouli (Harvard University, U.S.A.)

Instabilities in soft matter offer functionality and insights into material behavior. The first study examines squeaking in soft-rigid sliding interfaces, revealing that high-velocity sliding causes an elastic instability at the frictional interface in the form of opening pulses. These instabilities, when guided by thin ridges, lead to squeaking, offering new ways to control friction and energy dissipation by designing surfaces to either prevent or induce squeaking.

The second study investigates "metafluids" composed of highly deformable spherical capsules in an incompressible fluid. The buckling of these shells results in programmable compressibility, optical behavior, and viscosity. This instability-driven behavior enables advanced applications, including smart robotic systems, tunable logic gates, and switchable optical elements, showcasing the potential of metafluids to enhance fluidic device functionality.

Together, these studies underscore the importance of instabilities in soft matter for creating novel material properties and driving technological innovations.

Contact: Gwennou Coupier