Dresden 2026 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 37: Glasses and Glass Transition (joint session DY/CPP)
DY 37.2: Vortrag
Mittwoch, 11. März 2026, 11:45–12:00, ZEU/0118
Glass transition and universal scaling in ultra-low crosslinked microgels — Alessandro Martinelli1, Rajam Elancheliyan1, Andrea Scotti2, Alexander V. Petrunin3, •Domenico Truzzolillo1, and Luca Cipelletti1,4 — 1Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Universitè de Montpellier, F-34095 Montpellier,France — 2Division of Physical Chemistry, Lund University, SE-22100 Lund, Sweden — 3Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52074 Aachen,Germany — 4Institut Universitaire de France, F-75231 Paris, France
We investigate the glassy dynamics of Ultra-Low Crosslinked (ULC) poly(N-isopropylacrylamide) (PNIPAM) microgels. The glass transition is reached by varying either the temperature (modulating microgel swelling) or the colloidal number density. Our Dynamic Light Scattering (DLS) measurements confirm that the dynamic slowdown is solely governed by the effective volume fraction (ϕ), with ULC microgels behaving as fragile glass formers. Small-Angle X-ray Scattering data further indicates that the center-to-center inter-microgel distance is insensitive to temperature, scaling geometrically with mass fraction, while the height of the first peak of the static structure factor decreases with increasing concentration, suggesting structural melting above glass transition. We finally we report on the striking emergence of a universal dynamic behavior for the relaxation time (τα) dependence on the scattering vector (q) across the entire supercooled and glass regimes, allowing the data to collapse onto a master curve, whose features will be discussed.
Keywords: Colloidal glasses; Microgels; Ultra-low crosslinking; Light Scattering; X-ray Scattering