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SYCP: Symposium The Collapsed State of Polymers: From Physical Concepts to Applications and Biological Systems
SYCP 1: The Collapsed State of Polymers: From Physical Concepts to Applications and Biological Systems (CPP, BP, DY)
SYCP 1.5: Hauptvortrag
Donnerstag, 3. April 2014, 11:45–12:15, HSZ 02
Ring polymers in the melt state: the physics of crumpling — •Ralf Everaers1 and Angelo Rosa2 — 1Laboratoire de Physique et Centre Blaise Pascal, ENS Lyon, CNRS UMR5672, 46 allée d’Italie, 69364 Lyon, France — 2SISSA - Scuola Internazionale Superiore di Studi Avanzati, Via Bonomea 265, 34136 Trieste (Italy)
The conformational statistics of ring polymers in melts or dense solutions is strongly affected by their quenched microscopic topological state. The effect is particularly strong for non-concatenated unknotted rings, which are known to crumple and segregate and which have been implicated as models for the generic behavior of interphase chromosomes. Here we use a computationally efficient multi-scale approach to identify the subtle physics underlying their behavior, where we combine massive Molecular Dynamics simulations on the fiber level with Monte Carlo simulations of a wide range of lattice models for the large scale structure. We show that (i) topological constraints may be neglected on scales below the standard entanglement length, Le, (ii) that rings with a size 1 ≤ Lr/Le ≤ 30 exhibit nearly ideal lattice animal behavior characterized by primitive paths which are randomly branched on the entanglement scale, (iii) that larger rings are weakly swollen relative to ideal lattice animals with gyration radii ⟨ Rg2(Lr) ⟩ ∝ Lr2ν and ν≈ 1/d > 1/4, and (iv) that ring melts can be quantitatively mapped to coarse-grained melts of interacting randomly branched primitive paths.