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.

Effect of Wet and Dry Environments in CNC/MWCNTs/Ag2O Electrically Conductive Films: Material Characterization and Molecular Dynamics Simulation

“…Figure 2a,b shows derivative thermogravimetric (DTG) curves of CNC/MWCNTs (a) and CNC/MWCNTs/Ag 2 O (b) nanohybrid films during heating in nitrogen atmosphere as a function of carbon nanotubes content. As already observed in the case of CNC/SWCNTs, 9 thermal degradation of binary nanohybrids was delayed upon the addition of the carbon nanotubes, with an increase in DTG max values (from 0.15 to 0.20%min −1 ) and a shift of the main degradation event of CNC (measured at 192 °C) to 199 and 213 °C for CNC_3MWCNTs and CNC_5MWCNTs, respectively. This phenomenon results from the typical retardant effect of MWCNTs on the cleavage of the glycosidic linkages of cellulose.…”

“…The present work is an extension of our previous studies, concerning the physicochemical and electrical/dielectrical properties of two different types of binary systems based on CNC combined with single walled carbon nanotubes or silver nanoparticles . Here, we also analyzed the dependence of electrical transport properties on the synergistic interaction between MWCNTs and Ag 2 O NPs, in dry and in wet conditions.…”

“…It is worth noting that nanocellulose itself is not a conductor; thus, neat nanocellulose films exhibit low conductivity. 9 The dispersion of MWCNTs improves the conductivity, even at low MWCNT network has not been formed and the electric charge cannot effectively flow. By increasing the MWCNT content (up to 3 wt %), the conductivity improves significantly, as reflected in Figure 3a.…”

“…They are “rod-like” nanoparticles with crystallinity degrees ranging from 80 to 95% and large specific surface areas, which are also combined with unique structural and physicochemical properties . The hybridization of CNC with further nanomaterials permits to develop innovative and multifunctional biobased nanocomposites and efficient and sustainable devices for advanced applications with green properties in film and in 3D structure. , CNC is intrinsically insulating; however, it is a promising sustainable material for the preparation of conductive nanohybrid materials. CNC can be transformed into one that possesses electrically conductive properties by utilizing various modification strategies that harness their exceptional characteristics. − In particular, they can be applied as electric heaters, supercapacitors, and sensors, when combined with conductive nanofillers, , as shielding materials for excellent electromagnetic interference and as parts of electronics and communication devices …”

Dielectric Spectroscopy of PP/MWCNT Nanocomposites: Relationship with Crystalline Structure and Injection Molding Condition

“…Moreover, thanks to their tubular shape with a very high aspect ratio, they can turn the insulating behavior of polymers into conductive, even at very low content [ 2 ]. This is particularly interesting because a low CNT fraction does not modify the mechanical performance of the pristine polymer in which they are embedded, differently from other carbon-based additives (e.g., carbon black or graphite), which usually lead to brittle materials, due to the considerable amount needed to significantly modify the electrical behavior [ 3 , 4 , 5 , 6 , 7 , 8 ].…”