Regensburg 2025 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 6: Gels, Polymers Networks and Elastomers II
CPP 6.1: Vortrag
Montag, 17. März 2025, 15:00–15:15, H34
Scattering data of A4B4 model networks reveal structure induced apparent interaction and cross-link repulsion — •Reinhard Scholz and Michael Lang — Leibniz-Institut für Polymerforschung, Hohe Str. 6, 01069 Dresden, Germany
Based on computer simulations, we analyze how different forms of labeling the network components allow to extract complementary structural information from scattering data. The analysis relies upon simulations of hetero-complementary bound four-functional star polymers A4 and B4. For optimized contrast between A and B stars, the calculated dynamic scattering intensity resembles A-B block copolymers with an apparent repulsion between both components, accounting for ordering effects due to the complementary coupling scheme. The position of the observed scattering peak is compatible with radius of gyration and end-to-end extension of A-B chains connecting adjacent star centers, providing access to the mesh size of the network. In samples with optimum contrast, the static correlation length Ξ is in the same range but somewhat smaller than the respective correlation length for homogeneously labeled polymers. Choices of the scattering contrast focusing on the star centers or on small regions around these reveal a correlation hole. Accordingly, scattering is suppressed towards small wave vectors, allowing for a decomposition of the observed scattering intensity into a product of the form factor of the labeled star sections and a structure factor describing the distribution of cross-links in space.
Keywords: scattering contrast; model network; mesh size; correlation hole; form factor