A very first time the tunability of environmentally friendly Ethyl-Cellulose (EC)/Phosphate Graphene (PG) nanocomposites is explored by modulating the concentration of functionalized PG nanofillers. The work reported aims to understand the mechanisms of influencing the structural, optical, mechanical, and biological properties of EC-based nanocomposites for potential multifunctional applications via PG incorporation. Structural investigations by XRD reveal that increasing wt.% of PG nanofiller enhances crystallite size while reducing dislocation density and micro-strain. Simultaneously, energy density and mechanical flexibility reduce, as evidenced by increase in Young's modulus. Optical measurements indicate a notable narrowing of direct bandgap (5.02 eV-3.85 eV), accompanied by an increase in Urbach energy and refractive index. Enhancements in optical dielectric constants and optical conductivity with increasing the PG loading suggest intensified interfacial polarization and dipole interactions. Surface morphology and structural evolution are explored by FESEM along with EDAX and Raman spectroscopy, respectively, which is consistent with XRD findings. Furthermore, the nanocomposites exhibited concentration-dependent antioxidant and enzyme inhibition activities, with optimal biological performance observed at 5 wt.% PG. They also demonstrated stronger inhibition of alpha-glucosidase and alpha-amylase, suggesting improved interaction with enzymes. Thus, phosphate-functionalized graphene enhanced surface reactivity, validating EC/PG nanocomposites for flexible optoelectronics and eco-friendly packaging.
