Oriented Single-Walled Carbon Nanotubes–Poly(ethylene oxide) Nanocomposites

Abstract

The development of hierarchically ordered inorganic–polymer nanocomposites has traditionally focused on the nucleation of the crystalline, liquid crystalline, or ordered mesophase of the polymer by the inorganic nanoparticle. In this paper, we demonstrate the development of hierarchically ordered nanocomposites of semicrystalline poly(ethylene oxide) and aligned single-walled carbon nanotubes that is predicated on the disruption of the crystalline polymer by the nanoparticles. In lithium dodecyl sulfate compatibilized SWNTs–PEO nanocomposites, the amorphous segments of PEO chain largely surround the surfactant–nanotube adducts. These nanocomposites, when oriented by mechanical stretching, result in a templating of the polymer crystals with their lamellar-normals directed orthogonal to the nanotube axis. Oriented nanotubes, because of the short intertube distances even at low nanotube concentrations, govern the templated PEO crystal lamellae structure. The structures can be reconstructed after repeated heat to melt-hold-isothermal crystallization cycles under quiescent conditions. This observation provides the possibility of developing hierarchical nanocomposites with controlled multifunctional properties whose directionality can easily be manipulated. Specifically for PEO-based nanocomposites, oriented structure is beneficial for their use as solid electrolytes.