Packing Structure of Filamentous Matter

LEOPOLDO R. GÓMEZ

Erlangen

Seminario; CBI Colloquium; 2021

Friedrich Alenxander University

While linear polymers are well understood, the structure and dynamics of polymer rings remain elusive. Key concepts such as confining tubes and reptation, which are the cornerstone of polymer physics, could be misleading in the ring dynamics. Here we use commercial rubber bands imaged through X-ray tomography to compare the structural properties of semiflexible linear and ring assemblies. Individual band configurations in the assemblies are obtained through a machine learning segmentationapproach, allowing the detailed geometrical and topological characterization of the structures. Assemblies of short rings assume a liquid-like disordered structure, with short-range orientational order, and reveal only minor influence of the container. In the case of longer rings, the confinement causes folded configurations and the bands interpenetrate and entangle. Although rings tend to be more compact and display higher curvature, the topology of rings and linear assemblies are shown to be rather similar under confinement, when scaled properly.