Ordered carbon nanotubes–n-dodecyl tetraethylene monoether liquid crystal composites through phase separation induced by poly(ethylene glycol)

Abstract

Carbon nanotubes (CNTs) were incorporated into a lyotropic liquid crystal (LLC) matrix at room temperature through spontaneous phase separation. The phase separation process occurred in n-dodecyl tetraethylene monoether (C₁₂E₄) solutions induced by the hydrophilic polymer, poly(ethylene glycol) (PEG). It was found that the molecular weight of PEG has a significant effect on the CNTs–C₁₂E₄ system, which not only influences the phase behavior of the system but also changes the properties of the CNTs–LLC composites. Polarized optical microscopy (POM) images, combined with small-angle X-ray scattering (SAXS) results, indicate that CNTs incorporate within the layers of the lamellar LLCs without destroying the structure of LLCs. Moreover, UV-vis absorption, Raman spectra and rheological measurements were performed to investigate the characteristic properties of the CNTs–LLC composites. This study not only gives a more comprehensive understanding of polymer-induced phase separation, but also expands the potential uses of CNTs–LLC composites in nanotechnology.