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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 2: Modeling and Simulation of Soft Matter I

CPP 2.12: Talk

Monday, March 18, 2024, 12:45–13:00, H 0107

Viscosity of flexible and semiflexible ring melts - from molecular origins to flow-induced segregation — •Ranajay Datta, Fabian Berressem, Friederike Schmid, Arash Nikoubashman, and Peter Virnau — Institute of Physics, Johannes Gutenberg University, Staudingerweg 9, 55128 Mainz, Germany

We investigate with numerical simulations the molecular origin of viscosity in melts of flexible and semiflexible oligomer rings in comparison to corresponding systems with linear chains. The strong increase of viscosity with ring stiffness is linked to the formation of entangled clusters which dissolve under shear. This, together with an orientation of rings in shear direction lead to pronounced shear-thinning and non-Newtonian behaviour. Viscosity in linear chains on the other hand is associated with entanglements between chains which also dissolve under shear. While mixtures of flexible and semi-flexible rings mix under equilibrium conditions, differences in rheological properties induce separation under flow. This phenomena has potential applications in microfluidic devices and could be used to segregate stiffer semiflexible ring polymers from their fully flexible counterparts of similar mass and chemical composition.

Keywords: shear thinning; semiflexible ring polymers; clusters; entanglements; flow-induced segregation