Random-packing of semiflexible rings as a model for soft matter systems

NICOLÁS A GARCÍA; LEOPOLDO R. GOMEZ; BARRAT, JEAN-LOUIS; THORSTEN POESCHEL

Buenos Aires

Conferencia; StatPhys 27; 2019

A comprehensive understanding of the packing structure obtained by dense assemblies of semiflexible rings is not only fundamental for the dynamical description of polymers rings but also key to understanding bio-packaging, such as observed in circular DNA inside viruses or genome folding.In this work, we use X-ray tomography to study disordered packings of rubber bands in cylindrical containers as an athermal model for polymer rings and analogous system. Using advanced computational tools we detect and analyze the rings configurations in the packings at a single ring-level, characterizing the system geometrical and topologically. The degree of entanglement in the structures is quantified through minimal surfaces and generalized Voronoi tessellations. Averaging these observables over multiples equivalents configurations we found that packings of short bands conform a liquid-like disordered structure, with short-range orientational order and a minor influence of the container. On the contrary, for longer rings, confinement forces the band?s folding, and the rings interpenetrate and entangle. Most of the systems are found to display a threading network which percolates the system. Interestingly, for long bands whose diameter doubles the diameter of the container, we found that all bands interpenetrate each other, in a complex fully-entangled structure.