Enhanced optical and electrical properties of arrowroot starch films embedded with green synthesized silver nanoparticles

Biodegradable polymer nanocomposites are gaining wide recognition as sustainable and natural electrical and energy storage solutions. A facile solution casting approach was used to successfully develop eco-friendly nanocomposite films made of non- conventional and under explored arrowroot starch and green synthesized silver nanoparticles (Ag NP). UV-Vis spectroscopy reveals successful inclusion of nanoparticles by shifting the absorption peak of pristine starch from ~387 nm to wavelength range of ~474 nm to 720 nm. Photoluminescence experiments demonstrated enhanced emission in Ag NP-incorporated films, attributable to metal-enhanced fluorescence. XRD patterns indicate amorphous nature for both the samples with slight broadening of characteristic peaks of starch in the nanocomposite indicating structural alteration due to nanoparticle inclusion. SEM-EDS analysis revealed the presence of trace Ag NP inside the starch matrix. FTIR analysis visualizes the interaction of Ag NP with starch matrix. TEM Analysis depicts the starch matrix embedded with Ag NP and the SAED pattern shows the crystalline nature of Ag NP. At 100 Hz, the real impedance decreased significantly from 13.6 × 10⁵ Ω (starch) to 7.5 × 10⁵ Ω (nanocomposite). AC conductivity increased significantly, reaching 14.44 × 10⁻⁴ S m⁻¹ at 8 MHz, compared to 10.45 × 10⁻⁴ S m⁻¹ for pristine starch. Dielectric experiments demonstrated a lower dielectric constant and loss, resulting from reduced polarization effects due to inclusion of non-polar Ag NP. Cole-Cole plots showed increased charge transport and lowered relaxation resistance (from 16 × 10⁵ Ω to 9 × 10⁵ Ω). These findings indicate that Ag NP-incorporated arrowroot starch films have excellent optical and electrical properties, making them suitable candidates for biodegradable electronic and energy storage materials.