Nanopattern of the Inner Surface of Carbon Nanotubes for Self-Assembly of Nanoparticles: A Multistep Monte Carlo Method

摘要

We report a multistep Monte Carlo (MSMC) method which combines a canonical Monte Carlo (NVT) simulation for investigating the nanopattern of the inner surface of a hydrophobic carbon nanotube by surfactants and a grand canonical Monte Carlo simulation (GCMC) for exploring the self-assembly of nanoparticles in the surfactant-patterned carbon nanotube, where equilibrium configuration in the NVT simulation is used as an input in the GCMC. It is found from the NVT simulation that, as a small amount of surfactant is loaded in the carbon nanotube, the surfactants are self-assembled into a "strip" pattern parallel to the axis direction rather than a "ring" pattern or a spiral pattern, because the ring pattern or spiral pattern leads to more or less loss of the surface coverage, that is, loss of the surface entropy. In addition, the GCMC simulation result suggests that the nanoparticles self-assemble into an ordered layer on the substrate of the surfactant-patterned carbon nanotube, while the nanoparticles cannot enter the unpatterned hydrophobic carbon nanotube at all because of the unfavorable properties of nanoparticle with the carbon nanotube. In summary, the MSMC provides a powerful means for the nanopattern of the inner surface of a carbon nanotube for self-assembly of nanoparticles.