Dresden 2026 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 13: Charged Soft Matter, Polyelectrolytes and Ionic Liquids

CPP 13.3: Talk

Monday, March 9, 2026, 15:45–16:00, ZEU/0260

How polymer chain flexibility influences orientation and entanglements in polyelectrolyte solutions — Sascha Bartosch and •Ulrich Scheler — Leibniz-Institut für Polymerforschung Dresden e.V.

Entanglements in long-chain polymers are important for their mechanical properties and strongly impact the processability. In solutions the formation of entanglements depends on chain length, concentration and the chain flexibility. The flexibility of polyelectrolyte chains is influenced by the ionic strength of the solution that may screen the repulsive electrostatic interaction along the chain. That is reflected in the variation of the hydrodynamic radius of the polyelectrolytes measured by diffusion NMR. Upon shear polymers can orient or polymer chains maybe pulled out of entanglements. The NMR transverse relaxation time T2 is a good measure for the slow polymer-chain dynamics affected by polymer entanglements. Aligning polymer chains results in a shortened T2 while the loss of entanglements yielding longer chain segments between entanglements results in a longer T2. Short-chain polyelectrolytes under shear in a Searle cell show chain orientation. Long-chain polyelectrolytes at low ionic strength orient as well, while at higher ionic strength a loss of entanglements is observed. The transition from stiff to flexible entangled polymer is triggered solely by the electrostatic interaction modulated by the ionic strength under experimental control.

Keywords: polymer entanglements; polyelectrolyte; rheological NMR; polymer dynamics