Role of Mono- (Ag, Fe) and Bi- (Ag-Fe) metallic nanoparticles on EMI shielding and antimicrobial activity of PVA/ PVP blends - A green approach

Abstract

Abstract Plant-mediated solution casting is used to develop eco-friendly biopolymer blend nanocomposites from polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) embedded with Silver (Ag), Ferrous (Fe) monometallic and Silver-Ferrous (Ag-Fe) bimetallic nanoparticles (NPs). These nanocomposites were developed to understand their EMI shielding efficiency and antimicrobial activities, besides evaluating their physical and chemical properties using XRD, FTIR, FESEM, and EDX characterization techniques. The XRD spectra, revealed that the incorporation of nanoparticles into the blend has resulted in reduction the crystalline nature, significantly. For A3F3 it is reduced from 0.38 to 0.24. The results from FESEM, EDAX and the X-ray diffraction, all corroborate the presence of nanoparticles. The TGA tests reveal that the thermal stability of bimetallic composites is greater than that of monometallic composites, with sample A4F2 showing great improvement. The UTM study of mechanical characteristics showed that the addition of nanoparticles to the polymer matrix increased its mechanical strength. Among all nanocomposites, the A5F1 composite has shown higher tensile stress of 85.5 MPa and Young’s modulus of 7579.7 MPa. We examined its efficacy against Escherichia coli and Staphylococcus aureus and Candida albicans as microorganisms. Good antibacterial and antifungal activity was observed. The bimetallic composites demonstrated greater activity than monometallic composites against these bacterial and fungal species. All bimetallic nanocomposites have shown superior, loss due to reflection, loss due to absorption and the total EMI shielding efficiency at X- and Ku- bands. The samples A5F1 and A4F2, shown highest value of total EMI shielding efficiency of 18 and 32 dB at 8 and 16 GHz respectively. Enhanced antimicrobial, EMI shielding efficiency along with their physical properties, makes these nanocomposites suitable for food and medical packaging, coatings and EMI shielding applications.