Effect of the Reynolds and Richardson Numbers on the Growth of Well-Aligned Ultralong Single-Walled Carbon Nanotubes

Abstract

In this study, the effect of the Reynolds number (Re) and Richardson number (Ri) on the growth of well-aligned ultralong single-walled carbon nanotubes (SWNTs) has been systematically investigated. Smaller Re and larger Ri are favored for the growth of ultralong SWNTs by analyzing the fluid dynamical properties of chemical vapor deposition and the floating growth mode of ultralong SWNTs. Comparative experiments at different Re and Ri were carried out by altering the inner diameter of the quartz tube and gas flux in different growth processes. Growth results indicated that either reducing the gas flux or increasing the inner diameter of the tube, which corresponds to smaller Re or larger Ri, is beneficial for the growth of well-aligned ultralong SWNTs. On the other hand, too large a Ri, namely, a large buoyancy, is not suitable to grow parallel SWNT arrays for its disturbance to the laminar flow. The laminar flow and appropriate buoyancy are two vital factors for the growth of parallel and high-quality SWNT arrays.