Anomalous fluctuations of nematic order in solutions of semiflexible polymers

TL;DR

This study investigates the nematic order in solutions of semiflexible polymers, revealing anomalous fluctuations and proposing a new understanding of the isotropic-nematic transition through simulations and theory.

Contribution

It introduces a novel explanation for fluctuations in nematic phases of semiflexible polymers and validates a cylindrical confinement model using simulations and density functional theory.

Findings

Identification of anomalous fluctuations due to chain deflections

Validation of cylindrical confinement with effective radius r_eff

Insights into shortcomings of existing theories for the I-N transition

Abstract

The nematic ordering in semiflexible polymers with contour length $L$ exceeding their persistence length $\ell_p$ is described by a confinement of the polymers in a cylinder of radius $r_{eff}$ much larger than the radius $r_\rho$, expected from the respective concentration of the solution. Large scale Molecular Dynamics simulations combined with Density Functional Theory are used to locate the Isotropic-Nematic ($I-N$)-transition and to validate this cylindrical confinement. Anomalous fluctuations, due to chain deflections from neighboring chains in the nematic phase are proposed. Considering deflections as collective excitations in the nematically ordered phase of semiflexible polymers elucidates the origins of shortcomings in the description of the $I-N$ transition by existing theories.