Random-packed structures of rings as a model system of Soft Matter problems

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

Edimburgo

Conferencia; International Soft Matter Conference; 2019

Universidad de Edimburgo

Unraveling the packing structure of dense assemblies of semiflexible rings is not only fundamental for the dynamical description of polymers rings but also key to understanding biopackaging, 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. Using advanced computational tools we detect and study the rings configurations in the packings, characterizing the system at geometrical and topological level. The degree of entanglement in the structures is quantified through minimal surfaces and generalized Voronoi tessellations, allowing the identification of band´s threadings and neighbors. 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.