Dresden 2026 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 54: Gels, Polymer Networks and Elastomers II
CPP 54.3: Talk
Friday, March 13, 2026, 10:15–10:30, ZEU/0255
The Role of Connectivity Defects in Governing the Rheology and Microstructure of tPEG Networks — •Sayam Bandyopadhyay1,2, Sebastian Seiffert3, and Arash Nikoubashman1,2 — 1Leibniz-Institut für Polymerforschung Dresden e.V., Germany — 2Institut für Theoretische Physik, Technische Universität Dresden, Germany — 3Institut für Physikalische Chemie, Johannes Gutenberg-Universität, Germany
We utilized coarse-grained molecular simulations to examine how connectivity defects influence tetra-PEG (tPEG) polymer networks. Both homoleptic and heteroleptic systems were studied, with noncovalent end-group bonds modeled by an inverted Gaussian potential to control valency. Defects were introduced either by deactivating functional end groups or by deviating from ideal stoichiometry in heteroleptic mixtures. Post-gelation structure was quantified using structure factors, radial distribution functions of attractive beads, and internal loop statistics. Network dynamics and molecular mobility were assessed through mean-square displacements of individual tPEG molecules and through bond lifetimes. Our results show that defects enhance loop formation and substantially increase star-polymer mobility. As a consequence, networks with higher defect concentrations exhibit lower viscosity and faster stress relaxation. We also discuss the system's shear response simulated using a mesoscale solvent with hydrodynamic interactions to probe loop and link interconversion kinetics. These findings provide a molecular level understanding of how defects control the structure, dynamics, and mechanical properties of tPEG networks.
Keywords: gels; defects; dynamics; shearing; rheology