Regensburg 2019 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 38: Polymer Networks and Elastomers
CPP 38.1: Talk
Wednesday, April 3, 2019, 11:30–11:45, H18
Simulation and theory of model sliding-ring polymer systems — •Toni Müller1,2, Michael Lang1, and Jens-Uwe Sommer1,2 — 1Leibniz-Institut für Polymer- forschung Dresden — 2Technische Universität Dresden
In order to understand the elasticity of polymers which are harnessed by slidable rings such as polyrotaxanes we consider a simple model system. Here two chains are connected by crosslinking two of the slidable rings which act as stoppers for the other rings threaded on the chains. For the case of ideal chain statistics the partition function for chains under constant force can be calculated exactly and the resulting force-extension relations are compared with Monte Carlo simulations using the bond fluctuation model. We observe a strong strain-softening of the double-chain system under force which sharpens towards a jump-like transition of the elastic modulus for longer chains. We show that the reason for this behavior is fact that the slidable rings form a 1D real gas which is compressed by the stoppers if the chains are extended. Only if the external force exceeds the internal pressure caused by the slidable rings the chains can respond with the elastic compliance of their full contour related with a jump-like decay in modulus. Using simple thermodynamic arguments we calculate the critical force, and from an analytic approximation of the partition function we obtain the modulus of the connected chains in the low force region. Our system provides insights into a new class of elastic matter where conformational and internal degrees of freedom act together. A possible extension of our model are ’sliding-ring’ gels build-up from many sliding-ring polymers.