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MM: Fachverband Metall- und Materialphysik
MM 41: Development of Calculation Methods II
MM 41.1: Vortrag
Freitag, 13. März 2026, 10:15–10:30, SCH/A251
Atomistic Framework for Glassy Polymer Viscoelasticity Across 20 Frequency Decades — •Ankit Singh1, Vinay Vaibhav1, 2, Caterina Czibula3, Timothy W. Sirk4, and Alessio Zaccone1 — 1Department of Physics “A. Pontremoli", University of Milan, Via Celoria 16, 20133 Milan, Italy — 2Institut für Theoretische Physik, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany — 3Institute of Bioproducts and Paper Technology, Graz University of Technology, Inffeldgasse 23, 8010 Graz, Austria — 4US Army DEVCOM Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005, United States
Glassy polymers are central to engineering applications, yet their viscoelastic response over broad frequency and temperature ranges remains difficult to characterize. We extend non-affine deformation theory by incorporating a time-dependent memory kernel within the Generalized Langevin Equation for atomistic non-affine motions, yielding frequency-dependent mechanical response. Applied to poly(methyl methacrylate) (PMMA), the method captures the shear modulus and relaxation spectrum across more than twenty decades in frequency, from hundreds of terahertz down to the millihertz regime, thus bridging polymer mechanics from ordinary to extreme scales. Our predictions show quantitative consistency with independent estimates from oscillatory-shear molecular dynamics, Brillouin scattering, ultrasonic spectroscopy, Split-Hopkinson testing, and dynamic mechanical analysis (DMA), demonstrating a unified theoretical computational route for multiscale characterization of polymer glasses.
Keywords: Glassy polymer; Viscoelastic properties; Atomistic model; Non-affine theory; Beta relaxation