Robust chirality memory in carbon nanotubes growing under modulated and evolving environments

TL;DR

This study demonstrates that carbon nanotube chirality remains stable during growth despite dynamic environmental changes, highlighting the importance of nucleation control for chirality and challenging static growth models.

Contribution

It introduces a method combining isotope labeling and temperature modulation to track individual nanotube growth histories and reveals the robustness of chirality against environmental fluctuations.

Findings

Chirality remains preserved over lengths exceeding 300 micrometers.

Growth rates show hysteresis and high sensitivity to temperature changes.

Chirality control is established at the nucleation stage, not during elongation.

Abstract

Controlling the chirality and yield of carbon nanotubes is essential for their diverse applications from macroscopic composites to nanoelectronics. Floating-catalyst chemical vapor deposition is widely employed as a scalable synthesis route, where catalysts inevitably traverse spatially varying environments. However, prevailing interpretations of nanotube growth largely rely on ensemble monitoring or static, post-growth snapshots. Here, we combine digital isotope labeling with programmed temperature modulation to reconstruct the dynamic growth histories of supported individual nanotubes. Growth rates exhibit hysteresis and extraordinary sensitivity to temperature changes, indicating irreversible catalyst coarsening; nevertheless, the nanotube chirality remains robustly preserved across lengths exceeding 300 um. This sharp contrast between kinetic adaptability and structural memory in nanotube growth indicates that chirality control can be established at the nucleation stage, while allowing independent optimization of subsequent elongation. Our findings further call for a re-examination of static interpretations of diameter-determination mechanisms derived from post-growth snapshots.