Polymer Knots in Thin Films: Thickness Dependence, Local Effects, and Stiffness

TL;DR

This study investigates how confinement in thin polymer films influences topology, conformations, and stiffness, revealing a maximum knotting probability at intermediate thicknesses and layer-dependent structural effects.

Contribution

It provides a detailed analysis of thickness-dependent topological and conformational properties in polymer films, including explicit layer-resolved structural insights.

Findings

Knotting probability peaks near the bulk radius of gyration

Entanglement length increases near walls and conformations flatten

Layer-resolved analysis reconstructs explicit thickness dependencies

Abstract

We study how confinement affects topology and conformations in polymer films of varying thickness $h$. The knotting probability exhibits a maximum at intermediate thicknesses near the bulk radius of gyration $h \approx R_\mathrm{g,bulk}$, vanishes at small $h$ and approaches bulk values for large $h$. Close to walls, the entanglement length increases monotonically and conformations become flatter. A layer-resolved analysis of structural and topological properties allows us to reconstruct the explicit thickness dependencies by integrating layer-resolved properties of a thick film.