Dresden 2017 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 22: Polymer Networks and Dynamics II: Structure and Dynamics
CPP 22.10: Hauptvortrag
Dienstag, 21. März 2017, 12:15–12:45, ZEU 250
Molecular-level framework for the dynamic mechanical response and yielding of polymer glasses — •Alessio Zaccone1, Vladimir Palyulin1, Chris Ness1, Robert Elder2, Rico Milkus1, and Timothy Sirk2 — 1University of Cambridge, UK — 2US Army Research Laboratory, USA
Understanding the mechanical response of polymer glasses is currently one of the biggest challenges in polymer physics and soft matter. The deformation of polymer glasses has a considerable non-affine component at the monomer-unit level, meaning that every unit within every chain undergoes an additional displacement on top of the displacement imposed by the strain tensor [1]. We used theoretical and computational approaches, based on the non-affine molecular-level dynamics and on the vibrational density of states. A mechanistic assessment is obtained of how chemistry-dependent many-body angular constraints along the chain and cross-linking constraints affect: 1. the value of Tg (as parameterized also by the critical number of total nearest-neighbour units at the transition, z* [2]), 2. the rate-dependent elasticity/rigidity component of response, 3. the rate-dependent energy-absorption and ductility, and 4. the yielding transition [3]. This theoretical description poses the basis of a new chemical-design platform for linking polymer chemistry to mechanical performance in advanced polymer-based functional materials. [1] A. Zaccone & E.M. Terentjev, Phys. Rev. Lett. (2013). [2] A. Lappala, A. Zaccone, E.M. Terentjev, Soft Matter (2016). [3] V. Palyulin, C.J. Ness, R. Milkus, R. Elder, T. Sirk, A. Zaccone, in preparation.