Effect of SWCNT Content and Water Vapor Adsorption on the Electrical Properties of Cellulose Nanocrystal-Based Nanohybrids

Abstract

Cellulose nanocrystal (CNC)-based free-standing conductive films were prepared by introducing different contents of single-walled carbon nanotubes (SWCNTs) by an evaporation-induced self-assembly (EISA) process, using water as the sole solvent. The effect of SWCNT content on the morphology, thermal stability, and electric and dielectric properties of CNC films has been studied by field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). In order to investigate the effect of SWCNTs on the conduction mechanism of biobased nanohybrids, a detailed study on electrical and dielectric properties was conducted in DC and AC modes. The influence process parameters in terms of the dispersing agent and sonication method and the specific storage humidity conditions (RH = 0, 53, and 75%) were thoroughly investigated. The results arising from AC impedance spectroscopy were analyzed with respect to phase angle θ, the impedance imaginary part, and Nyquist plots, revealing the pivotal role of both SWCNT concentration and relative humidity in the electrical properties of nanohybrids. As a result, this work sheds light on the conducting mechanism of films based on cellulose nanoparticles in the presence of carbonaceous nanofillers.