Solubilization of functionalized (5,5) single-walled carbon nanotubes in 5CB nematic liquid crystals: simulation using Flory-Huggins theory

This work analyzes the solubility behavior between a 4'-n-pentyl-4-cyano-biphenyl (5CB) liquid crystal and a maleic anhydride (MA)-grafted surface-modified (5, 5) single-walled carbon nanotube (SWCNT-MA) using the Flory-Huggins model. The statistical thermodynamics of the Flory-Huggins mean-field theory, and its extension to modeling of macromolecular or polymer solutions, is adopted for the first time to investigate solubility as it is related to blending of liquid crystals with carbon nanotubes. This theory incorporated with Monte Carlo calculation reveals that, at room temperature, this functionalized carbon nanotube with all regular commonly seen CNT lengths can spontaneously and fully dissolve in 5CB nematogen when the grafting ratio of the MA functional group reaches 30 at. wt%. We believe that this mesoscale simulation offers a reliable and useful analytical method for 'liquid crystal soluble' carbon nanotubes, since this novel composite material can form a homogeneous nanosolution, and realize its potential in the future.