Nanocomposite Foils of PS/Cu : Dual Functionality of Optical Enhancement and Antibacterial Activity on Aeromonas hydrophila

Copper nanoparticles embedded in polystyrene (PS) nanocomposite foils were prepared via the solution casting method to study their optical characteristics and antimicrobial activities. Structural and surface morphology of the prepared nanocomposite foils were carried out by FTIR and FESEM. UV–vis spectra reveal that the nanocomposite foils are optically transparent in the visible region, with a strong absorbance peak at ~ 264 nm. Optical parameters such as optical band gap (E_g), refractive index (n), extinction coefficient (k), and dielectric constants (ε₁, ε₂, tanδ) were calculated using UV–vis spectroscopy. The Single Oscillator Wemple DiDomenico model was employed to determine the dispersion energy characteristics (E₀, E_d), optical moments (M_-1, M_-3), and dispersion of refractive index (n₀). The nonlinear index of refraction (n₂) and third-order optical nonlinear susceptibility (χ³) were calculated using Miller’s expression. In-vitro antimicrobial activity was tested against Gram-negative bacterial species isolated from a hospital wastewater treatment plant, showing multiple drug resistance activity. The study revealed that PS/Cu nanocomposite foils exhibit promising results as optical limiters with significant antibacterial activity.