Cashew gum/boehmite bio-nanocomposite films: A promising platform for flexible Nano-dielectric devices

This work focused on fabricating bio-nanocomposite films from cashew gum (CG) and boehmite (BHM) using a water-based solution casting technique, followed by comprehensive characterization through various analytical techniques. XRD and FTIR analyses confirmed the presence of characteristic BHM peaks and its successful integration into the CG matrix. Tauc's plot revealed a decreasing optical bandgap with increasing BHM content, likely due to the introduction of new energy states and structural changes in the CG matrix. FE-SEM and HR-TEM revealed significant morphological changes in the composites, indicating effective dispersion and interaction between CG and BHM. The thermal stability of CG improves with increasing BHM nanoparticle loading. Mechanical testing showed a 47 % increase in tensile strength for the CG/5 wt% BHM film, with only a slight reduction in elongation at break. Electrical properties, including AC conductivity, dielectric constant, loss tangent, electric modulus, and impedance were evaluated across various frequencies and temperatures. AC conductivity increased with frequency, while dielectric constant and loss tangent decreased. Furthermore, the electrical parameters increased with temperature and were strongly influenced by the BHM content. Notably, the CG/5 wt% BHM nanocomposite exhibited the highest conductivity and dielectric constant at ambient temperature, approximately twofold and threefold greater, respectively, than pure CG. These results underscore the promising potential of CG/BHM bio-nanocomposites for use in flexible nano-dielectric devices and energy storage applications.