Polyethylene under tensile load: strain energy storage and breaking of linear and knotted alkanes probed by first-principles molecular dynamics calculations

TL;DR

This study uses first-principles molecular dynamics to analyze how tension affects polyethylene chains, revealing that knots weaken the chain and cause rupture outside the knot, with distinct strain energy distributions.

Contribution

It provides detailed insights into the mechanical behavior of knotted versus linear polyethylene chains under tension using first-principles simulations.

Findings

Knots significantly weaken polyethylene chains.

Rupture occurs just outside the knot entrance.

Strain energy distribution differs markedly between linear and knotted chains.

Abstract

The mechanical resistance of a polyethylene strand subject to tension and the way its properties are affected by the presence of a knot is studied using first-principles molecular dynamics calculations. The distribution of strain energy for the knotted chains has a well-defined shape that is very different from the one found in the linear case. The presence of a knot significantly weakens the chain in which it is tied. Chain rupture invariably occurs just outside the entrance to the knot, as is the case for a macroscopic rope.