Confined chiral polymer nematics: ordering and spontaneous condensation

TL;DR

This study models the condensation of chiral nematic polymers like DNA inside spherical confinements, revealing how boundary conditions and chirality influence the formation of complex, toroidal, and surface condensates similar to biological structures.

Contribution

It introduces a Landau-de Gennes free energy framework for confined chiral nematic polymers, analyzing how boundary interactions and chirality drive diverse condensate morphologies.

Findings

Chirality induces a transition from toroidal to higher-genus condensates.

Boundary conditions significantly affect the condensate structure.

Chiral nematic polymers form complex surface condensates resembling viral DNA packaging.

Abstract

We investigate condensation of a long confined chiral nematic polymer inside a spherical enclosure, mimicking condensation of DNA inside a viral capsid. The Landau-de Gennes nematic free energy {\sl Ansatz} appropriate for nematic polymers allows us to study the condensation process in detail with different boundary conditions at the enclosing wall that simulate repulsive and attractive polymer-surface interactions. Increasing the chirality, we observe a transformation of the toroidal condensate into a closed surface with an increasing genus, akin to the ordered domain formation observed in cryo-microscopy of bacteriophages.