Enhanced optical, mechanical, thermal, and antibacterial properties in polymer bio-nanocomposites films via loading Ag/Au nanoparticles for optical devices and food packaging

Abstract

Utilizing a solution cast process, polymer nanocomposites (PNCs) consisting of a host matrix of Chitosan (Cs)/Polyacrylamide (PAM) as a blend, silver nanoparticles (Ag NPs) (1 wt%), gold nanoparticles (Au NPs) (1 wt%), and mixed Ag/Au NPs (2 wt%) as a nanofiller are created. According to the X-ray Diffraction (XRD) study, the blend's degree of crystallinity decreased with the adding of Ag and Au NPs, and the 2%Ag/Au NPs-CS/PAM film had the optimal amount of amorphousness. The Transmission electron microscopy (TEM) pictures reveal the almost spherical form of Ag NPs and Au NPs. The addition of nanoparticles to the polymer blend alters the intensity and broadens the peaks of certain functional groups, which causes a considerable interaction of the Cs/PAM chains and nanoparticles in the PNCs, as shown by the Fourier transform infrared spectroscopy (FTIR) spectra. The UV–Vis analysis indicated that the optical properties of the synthesized Ag/Au NPs-Cs/PAM nanocomposites, such as both direct and indirect bandgap energies, show a decrease in the optical energy gap when the concentration of mixed nanoparticles within the Cs/PAM host matrix is added. In addition, the EU value at 2%(Ag/Au NPs)-Cs/PAM is higher than other samples. According to the thermogravimetric (TGA) study at 450 °C, the nanocomposite 2% Ag/Au-CS/PAM weight loss was 32.5%, while the pure blend was 58.3%. The nanocomposites with 2% Ag/Au NPs outperformed virgin CS/PAM by 72.8%, 90.34%, and 92.59%, respectively, in terms of Young's modulus, elongation at break, and tensile strength. Additionally, Ag/Au NPs-induced Cs/PAM nanocomposites demonstrated strong antioxidant and antibacterial activity against S. aureus, P. aeruginosa, E. coli, B. subtilis, and C. albicans. Furthermore, when compared to other samples, the mixed Ag/Au NPs incorporated in the Cs/PAM blend film enhanced the optical, thermal, mechanical, and antimicrobial properties more effectively. This verifies the prepared bio-nanocomposites' potential for use as an active food packaging material and in optoelectronic applications. Highlight: Ag/Au-PAM/CS nanocomposite was successfully prepared by the casting method. The prepared films also showed good optical properties. CS/PAM composite with Ag/Au mixed NPs has a good thermal stability. CS/PAM composite with 2 wt% nanofiller has excellent antibacterial activity. The Ag/Au-PAM/Cs sample was suggested to be used in food packaging.