Dresden 2020 – wissenschaftliches Programm
Die DPG-Frühjahrstagung in Dresden musste abgesagt werden! Lesen Sie mehr ...
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 72: Polymer Networks and Elastomers
CPP 72.2: Vortrag
Mittwoch, 18. März 2020, 15:30–15:45, ZEU 114
Swelling of tendomer networks: a model system for topological gels — •Toni Müller1,2, Michael Lang1, and Jens-Uwe Sommer1,2 — 1Leibniz Institute of Polymer Research Dresden, Germany — 2TU Dresden, Germany
A polyrotaxane (PR) consists of many small cyclic molecules ("rings") threaded onto a long polymer chain where stopper monomers at the chain ends prevent detachment of the rings. Polymer networks can be constructed by linking the rings in solution of PRs. We discuss the tendomer as a model system where only their very first rings of the PRs are connected while all remaining rings, m, form a one-dimensional repulsive gas along the PR. Pulling on pairs of chain ends next to the connected rings induces a compression of the sliding rings confined on the two chains. We investigate the force extension relation of the tendomers by computer simulations and compute numerically the exact solution of full partition function in the constant force ensemble. Our results show that tendomers are stiff for low applied forces and soften dramatically when reaching a stall force that is triggered by the density of non-crosslinked rings on the PRs. For large deformations, the finite extensibility of the chains results again in a lower susceptibiliy regarding an applied force [1]. These results are inserted into the Flory-Rehner model predicting the equilibrium degree of swelling, Q, of gels made by crosslinking tendomers. We find that Q scales with m by a power law of 3/4 and that entanglements are negligible.
[1] Müller, T., Sommer, J.-U., Lang, M. (2019) Soft Matter, 15(18), 3671-3679