Structure, morphology, and optical properties of polyacrylamide/poly (vinyl alcohol) (PAM/PVA) polymer blend...

Manganese Dioxide (MnO₂) nanoparticles were incorporated into a Polyacrylamide/Polyvinyl Alcohol (PAM/PVA) polymer blend via solution casting to investigate the influence of MnO₂ content (0.1, 0.5 and 1.0 wt%) on the composite's structural and optical behavior. The novelty of this work lies in demonstrating that the incorporation of very low MnO₂ concentrations effectively modifies the optical properties of the PAM/PVA blend while preserving its structural integrity through strong interfacial interactions, providing an efficient strategy for tuning polymer nanocomposite performance. X-ray diffraction confirmed the semi-crystalline nature of PAM/PVA blend and successful incorporation of MnO₂ nanoparticles without altering the polymer matrix, while Fourier transform infrared (FTIR) spectroscopy indicated strong interfacial interactions between the polymer matrix and MnO₂ surface species, suggesting the presence of chemical bonding and modified local electronic environments. Scanning electron microscopy (SEM) and energy- dispersive X-ray (EDX) mapping demonstrated uniform nanoparticle dispersion at low concentrations and the emergence of agglomeration at higher concentrations, with corresponding changes in surface morphology. UV-Vis spectroscopy indicated progressively enhanced absorption and a systematic reduction in the optical band gap from 4.27 eV (pristine) to 4.00 eV (1 wt.%MnO₂), accompanied by an increase in the refractive index. The tunable optical response of PAM/PVA-MnO2 nanocomposites highlights their potential for applications in flexible optoelectronics, sensors, and energy storage devices.