Multifunctional polyvinyl alcohol / <i>maranta arundinacea</i> starch /LiAgO nanocomposites: A sustainable approach for antibacterial and optoelectronic applications
N. Najmu Shabah, TT Khaleelul Rahman, R. Gopika, M. T. Ramesan
Abstract
Researchers are actively exploring sustainable alternatives to conventional materials through the development of biopolymer nanocomposites (NCs). In this study, blend NCs of polyvinyl alcohol (PVA) and Maranta arundinacea starch, reinforced with lithium silver oxide (LiAgO) nanoparticles (NPs), were synthesised using water as a green solvent. The successful incorporation of LiAgO into the polymer matrix was confirmed by Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD), which revealed characteristic peaks of the nanoparticles. UV-visible spectroscopy showed enhanced optical absorbance with increasing LiAgO concentration, with the 9 wt% nanocomposite showing optimal performance, including the lowest bandgap and highest refractive index. Scanning electron microscopy (SEM) revealed uniform nanoparticle dispersion at 9 wt%, whereas higher concentrations led to agglomeration. Thermal analysis showed improved thermal stability in NCs with the inclusion of LiAgO compared to a pure polymer blend. Impedance analysis showed that NCs exhibited improved electrical conductivity and dielectric properties, with 9 wt% nanocomposite achieving the highest AC conductivity of 1.4 × 10 −6 S/cm at 110°C. Mechanical testing further confirmed that the 9 wt% nanocomposite demonstrated significant improvements in tensile strength, Young’s modulus and surface hardness, accompanied by reduced elongation at break. Antibacterial assay against Escherichia coli showed increasing antimicrobial efficacy with higher NP content, with the 12 wt% NC displaying the largest inhibition zone. These findings underscore the potential of PVA/ Maranta arundinacea starch /LiAgO NCs as biodegradable, multifunctional materials for optoelectronic and antibacterial applications.