# Hydrogenation and Entanglement Effects on Tensile Properties and Energy Absorption of Entwined Coiled Carbon Nanotubes: A Molecular Dynamics Study

## TL;DR

This study uses molecular dynamics to explore how hydrogenation and entanglement affect the mechanical properties and energy absorption of coiled carbon nanotubes.

## Contribution

The study reveals the dual regulatory effects of hydrogenation and the benefits of entanglement on the performance of coiled carbon nanotubes.

## Key findings

- Moderate hydrogenation enhances tensile strength and energy absorption, while excessive hydrogenation causes brittleness.
- Entanglement increases the tensile load-bearing capacity and energy absorption of coiled carbon nanotubes by 1.5–2.0 times.
- ECCNT2 achieves the best balance between tensile stiffness, ductility, and energy absorption efficiency.

## Abstract

Coiled carbon nanotubes and their entwined derivatives have attracted attention for their excellent mechanical properties and potential applications. Hydrogenation is an effective way to modify the mechanical response of CCNTs, but its effect on the tensile performance and energy absorption of ECCNTs remains unclear. In this study, molecular dynamics simulations are used to systematically investigate the regulatory effects of hydrogenation and entanglement on the tensile properties and energy absorption capacity of CCNTs and ECCNTs. Different hydrogenation degrees and structural configurations are designed for comparative analysis. Results show that hydrogenation exerts a dual regulatory effect on single CCNTs: moderate hydrogenation enhances tensile strength and total energy absorption, while excessive hydrogenation leads to brittleness, reduced ductility, and impaired energy dissipation. Entanglement significantly improves the tensile load-bearing capacity and energy absorption of CCNTs, with ECCNTs showing 1.5–2.0 times higher spring constants than single CCNTs. Among the ECCNT models, ECCNT2 achieves an optimal balance between tensile stiffness, ductility, and energy absorption efficiency. This study clarifies the mechanistic roles of hydrogenation and entanglement, providing valuable guidance for the rational design of high-performance CCNT-based structural and functional nanomaterials.