Capillary Absorption of Metal Nanodroplets by Single-Wall Carbon Nanotubes

Abstract

We present a simple model that demonstrates the possibility of capillary absorption of nonwetting liquid nanoparticles by carbon nanotubes (CNTs) assisted by the action of the Laplace pressure due to the droplet surface tension. We test this model with molecular dynamics simulation and find excellent agreement with the theory, which shows that for a given nanotube radius there is a critical size below which a metal droplet will be absorbed. The model also explains recent observations of capillary absorption of nonwetting Cu nanodroplets by carbon nanotubes. This finding has implications for our understanding of the growth of CNTs from metal catalyst particles and suggests new methods for fabricating composite metal-CNT materials.

Catalyst-particle configurations: From nanowires to carbon nanotubes

“…3, 4). The analysis covers the withdrawal and uptaking processes of droplets from the CNTs, which is different from the works that focus on the penetration process [6,[11][12][13][14][15]. Thus, the present analysis also augments the theory to dynamic processes and possible equilibrium states of liquid droplets atop capillary tubes, especially for tubes in which the thickness of the wall cannot be neglected.…”

“…A. Gohiera et al [5] observe that the ratio between diameters of the catalyst and the single-wall carbon nanotubes (SWCNTs) is close to a constant and independent of other experimental conditions. Schebarchov et al [6], using a simple model and molecular-dynamic simulation, finds that nonwetting molten nanoparticles below a critical size can enter the interior of single wall CNTs in the process of base growth. In the growth of multi-wall carbon nanotubes (MWCNTs), the catalyst particles seem to display pearlike shapes which oscillate in time.…”

“…The droplet penetration into capillary tubes, pipettes [6,[11][12][13][14] or pores [15] has been investigated both theoretically and numerically in the past. In all the previous theoretical analyses, it has been assumed that the droplet contacts the tube inlet [6,[11][12][13][14], or spreads along the top face [15].…”

“…In all the previous theoretical analyses, it has been assumed that the droplet contacts the tube inlet [6,[11][12][13][14], or spreads along the top face [15]. This assumption is valid for thin tube walls or SWCNTs.…”

The effect of carbon nanotube chirality on the spiral flow of copper atoms in their cores

“…Through various experiments and simulations [7,8], the studies on the filling of metal atoms in CNTs have been carried out extensively in order to demonstrate the method and outcome of the filling processes. Zhang and Wang have filled CNTs with copper atoms using a method based on a microwave plasma-assisted chemical vapour deposition system [9], whereas Schebarchov and Hendy have shown the capillary effect of palladium atoms in CNTs using molecular dynamics (MD) simulations [10,11]. Another important study, which shows the mechanical and structural properties of metal nanowires, CNTs and metal-filled CNTs, is conducted by Soldano and Mariscal on the iron-filled CNTs using simulations [12].…”