Carbon Nanotube/Graphene Nanoribbon/Polyvinylidene Fluoride Hybrid Nanocomposites: Rheological and Dielectric Properties

Results of the present study demonstrate the potential of graphene nanoribbon to induce giant synergistic effects in the broadband dielectric properties of multiwalled carbon nanotube/graphene nanoribbon/polyvinylidene fluoride (MWCNT/GNR/PVDF) nanocomposites. The nanocomposites were prepared using a melt-mixing technique at various nanofiller total contents and MWCNT/GNR weight ratios. Rheology coupled with AC conductivity measurements of the nanocomposites unearthed highly superior capability of MWCNT to neighbor or interlace compared to GNR; i.e., the MWCNT has higher ability to participate in a percolative network. Broadband dielectric spectroscopy demonstrated superior dielectric properties for MWCNT/GNR/PVDF ternary (hybrid) nanocomposites compared to the MWCNT or GNR binary nanocomposites. For instance, at 1.5 wt % and 1000 Hz, the ternary nanocomposite with an MWCNT/GNR ratio of 3:1 presented a real permittivity and dissipation factor of 41.4 and 0.91, surpassing the binary MWCNT nanocomposite with a real permittivity and dissipation factor of 39.3 and 86.7, respectively. We attribute this synergistic effect to the poor interlacing ability of GNRs, as secondary conductive nanofillers, acting as extra nanoelectrodes. In fact, the role of GNRs as extra nanoelectrodes in conjunction with their poor propensity to bridge MWCNTs led to effective nanocapacitor structures with low energy loss.