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Loose or Tight: When Knots Sit on Polymer Rings

26 March 2018

Knots on polymers occur regularly in nature – the longer the polymers are, the more likely this is to happen. Of particular importance are, for example, knots on viral DNA, which strongly impact the dissemination of the knots out of the viral capsule.

How do these microscopic objects behave in shear fluid? Maximilian Liebetreu and Christos Likos from the University of Vienna along with Marisol Ripoll from the Jülich Institute for Theoretical Soft Matter and Biophysics (ICS-2 / IAS-2) have now studied this question using computer simulations. Primarily, the difference between knotted and unknotted rings was central to their research, in the case of hydrodynamic interactions.These findings could be useful in developing a method to separate the two different ring types.

Polymer-knotsTrefoil knotted ring under strong shear in its loosened state. The red area highlights the knot, and the axis labels correspond to (x,y,z) = (flux, gradient, vorticity) directions. Such loosened configurations prevail at very high shear rates due to the presence of hydrodynamic interactions.
Copyright: Maximilian Liebetreu, University of Vienna

Original publication:

Maximilian Liebetreu, Marisol Ripoll and Christos N. Likos:
Trefoil Knot Hydrodynamic Delocalization on Sheared Ring Polymers.
ACS Macro Letters 2018. DOI: 10.1021/acsmacrolett.8b00059

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