Terahertz characterization of multi-walled carbon nanotubes/high-density polyethylene nanocomposites

Terahertz (THz) technology is a fundamental and vital technology that is expected to be crucial to building future-generation wireless communication systems. To develop THz devices and systems, it is necessary to study the electrical, optical, and optoelectronic properties of various functional materials in the THz band. In this study, the THz optical and electrical properties of multi-walled carbon nanotube/high-density polyethylene (MWNT/HDPE) nanocomposites were investigated in the frequency range of 0.2–4.0 THz using THz time-domain spectroscopy. MWNT/HDPE composite samples with 1, 3, 5, and 7% MWNT content by weight were fabricated by twin-screw extrusion and injection molding. Using THz spectroscopy in the transmission geometry at room temperature under a dry air atmosphere, the THz complex refractive index, permittivity, and conductivity of these samples were determined. The results show that the optical and electric properties of these nanocomposites can be efficiently tuned by changing the MWNT weight fraction. The Drude–Lorentz model, together with the Maxwell–Garnet effective medium theory, was applied to investigate the transport parameters of composites. The THz spectroscopic analysis shows that MWNTs act as nucleating agents and contribute to crystallization in the polymer nanocomposites.