Helices at Interfaces

TL;DR

This paper investigates the behavior of helically coiled filaments confined to two dimensions, revealing their complex conformations and statistical mechanics through theory and simulations, highlighting the role of twist-kinks in their dynamics.

Contribution

It introduces a novel theoretical and simulation framework to understand 2D confined helices and identifies twist-kinks as key entities governing their behavior.

Findings

Confined helices form looped, spiral, or circular conformations.

Filaments can switch between topological twist states thermally.

Some states show increased circularization and hyperflexibility.

Abstract

Helically coiled filaments are a frequent motif in nature. In situations commonly encountered in experiments coiled helices are squeezed flat onto two dimensional surfaces. Under such 2-D confinement helices form "squeelices" - peculiar squeezed conformations often resembling looped waves, spirals or circles. Using theory and Monte-Carlo simulations we illuminate here the mechanics and the unusual statistical mechanics of confined helices and show that their fluctuations can be understood in terms of moving and interacting discrete particle-like entities - the "twist-kinks". We show that confined filaments can thermally switch between discrete topological twist quantized states, with some of the states exhibiting dramatically enhanced circularization probability while others displaying surprising hyperflexibility.