Significantly improved dielectric performance of bio-inspired gelatin/single-walled carbon nanotube nanocomposite

In this study, the dielectric properties of gelatin/single-walled carbon nanotube (Gel/SWCNT) nanocomposite were evaluated. The nanocomposites were synthesized by a simple solution casting method. The electron transport properties of the nanocomposites were studied by the dielectric and impedance spectroscopy techniques. A dielectric constant as high as 104 and a loss tangent of 0.91 were obtained for the Gel/SWCNT nanocomposite material at 100 Hz. The dielectric permittivity data of the nanocomposites were fitted by the modified Cole–Cole model to estimate the dielectric strength and the relaxation time. The addition of SWCNT into the gelatin reduces the relaxation time of the nanocomposite from 3.03 to 1.01 μs. The complex impedance spectra analyses show an increase in alternating current conductivity due to the incorporation of SWCNT and can be attributed to the change in bulk resistance together with a reduction in relaxation time of the nanocomposite. A quantitative analysis from the fitting of the Cole–Cole plot also reveals that the incorporation of SWCNT into the nanocomposite decreases the grain boundary resistance from 16 950 to 53 kΩ and increases the capacitive element from 67 to 275 nF. The mechanism behind the improved dielectric performance of the Gel/SWCNT nanocomposites has been elucidated in this study.