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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 59: Crystallization

CPP 59.4: Vortrag

Freitag, 13. März 2026, 12:15–12:30, ZEU/0260

Interplay of heterogeneous nucleation and prefreezing in PBS droplets on graphene — •Marthinus van Niekerk, Moritz Hartelt, and Oleksandr Dolynchuk — Experimental Polymer Physics, Martin-Luther-University Halle-Wittenberg, Germany

The dominant crystallization mechanism depends on the kinetics of formation and crystal growth. Heterogeneous nucleation, leading to spherulitic morphology, and prefreezing, leading to epitaxial morphology, are two mechanisms of interface-induced crystallization in polymers. However, research on prefreezing is in a seminal phase, and its possible competition with nucleation during cooling remains unexplored. Here, we study the crystallization behavior of dewetted poly(butylene succinate) (PBS) droplets on graphene, a known prefreezing substrate for PE and PCL, during cooling from the melt at different rates using optical- and atomic force microscopy and wide-angle X-ray scattering. Across a large range of cooling rates, nucleation was found to be dominant, resulting in spherulitic morphology in large droplets. However, indications of prefreezing were observed in very small droplets exhibiting epitaxial morphology. Subsequent annealing close to T_m resulted in significant reordering and enhancement of out-of-plane orientation, causing a change in morphology from spherulitic to epitaxial for all droplets up to several hundred nanometers. Theoretical analysis revealed a significant lattice mismatch between graphene and PBS, suggesting it is a plausible reason for the absence of rapid prefrozen layer growth during initial cooling from the melt.

Keywords: Prefreezing; Heterogeneous nucleation; Crystallization; Interfaces; Substrates