Regensburg 2016 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

DY: Fachverband Dynamik und Statistische Physik

DY 55: Polymer Dynamics and Rheology (joint session CPP/DY, organized by CPP)

DY 55.6: Vortrag

Donnerstag, 10. März 2016, 16:15–16:30, H40

Disentanglement of Two Overlapping Polymer Chains: Contacts vs. Knots — •Diddo Diddens, Nam-Kyung Lee, Sergei Obukhov, Jörg Baschnagel, and Albert Johner — Institut Charles Sadron, Université de Strasbourg, CNRS UPR22, 23 Rue du Loess, 67034 Strasbourg Cedex 2, France

The role of topological constraints is one of the remaining challenges in polymer physics. While it is evident that the non-crossability heavily affects the motion of long polymer chains in dense solutions and melts, these constraints are usually neglected in theoretical descriptions of the polymer dynamics in dilute solutions. However, the situation becomes less clear in the limit of long chains and/or rather dense polymer coils (e. g. close to the Θ-point), since even for a single chain, distinct segments are more likely to be intertwined or knotted.

To address this issue, we present a comprehensive study comprising MC and MD simulations as well as analytical calculations, and investigate the relevance of non-crossing constraints for two polymer chains brought into initial overlap. In particular, we join two long polymers by a labile bond, and focus on their separation directly after the cleavage of this bond. We demonstrate that the average time for this process strongly correlates with the number of monomeric contacts between the two strands. Moreover, in case of highly entangled or knotted starting configurations, the segregation time is several orders of magnitude larger than expected for a purely diffusive process, thus clearly highlighting the importance of topological constraints. Finally, we also give a brief account on the role of hydrodynamics.