Improving the characteristics, optical and electrical features of a biopolymer blend <i>via</i> <scp>silver–</scp> multiwalled carbon nanotube nanocomposites for practical applications

Abstract Environmental perspectives have forced researchers to develop novel electrolytes/nanocomposites based on biopolymers for recent and future technological applications. In this study, multiwalled carbon nanotubes (MWCNTs) and AgNO 3 were incorporated into bio‐blend films through the solution casting process. Fourier transform IR and XRD indicated that the fillers interacted and formed complexes with the blend's functional groups and increased the amorphous areas. Field emission SEM/energy dispersive spectroscopy techniques showed the compatibility between the blend and fillers and an even filler distribution at the atomic level. The UV–visible–near IR revealed that loading MWCNTs and AgNO 3 resulted in almost zero transmittance in the UV and blue light regions. The k ‐index spectra exhibited a symmetrically shaped surface plasmon resonance at λ = 423 nm, which means that nano‐sized Ag was formed. The direct (indirect) bandgap of the blend is 4.3 (4.2) eV, reduced to 4.0 (3.9) eV upon loading MWCNTs and to 3.6 (2.3) eV when AgNO 3 is introduced. Moreover, after the additives, the blend exhibited a dual bandgap nature. The materials have DC and AC conductivities in the range (3.27–43.32) × 10 −8 S cm −1 and (6.98–63.10) × 10 −5 S cm −1 (at 1.0 MHz), respectively. Both the dielectric permittivity and loss were enhanced by MWCNTs and AgNO 3 incorporation. The dielectric moduli formalism revealed the existence of multiple relaxation mechanisms. The impedance exhibited a reverse behaviour to that of conductivity and confirmed that the conduction mechanism follows the Cole–Cole model. The findings of this study reveal that the AgNO 3 /MWCNTs/blend has a promising usage in flexible dielectrics and bandgap‐adjustable materials for micro‐optoelectronics, photonics, shielding and food packaging applications. © 2025 Society of Chemical Industry.