Soft Matter and Complex Systems Seminar

Chains of metal beads knotted to a topology of a torus knot, settling under gravity in a very viscous silicon oil, tend to stabilize in the form of extended, flat, tightly interwound toroidal structures. In this configuration they perform an oscillatory motion of the loops swirling periodically around each other. Owing to hydrodynamic similarity, micro-chains in water are expected to behave in the same way. Stokesian dynamics simulations of elastic knotted closed fibers confirm the long-lasting character of such toroidal structures and their swirling motion, accompanied by rotation. The main conclusion is that dynamics of topologically complex flexible microobjects in fluids can lead to formation of complex ordered structures. This finding may be important for understanding centrifugation and sedimentation experiments with DNA, proteins or other biological systems.

M. Gruziel, K. Thyagarajan, G. Dietler, A. Stasiak, M. L. Ekiel-Jezewska, P. Szymczak, Physical Review Letters, 121, 127801, 2018.