Hydroxyapatite nanoparticles reinforced polyvinyl alcohol/chitosan blend for optical and energy storage applications

Biopolymer blend nanocomposite films composed of polyvinyl alcohol (PVA) and chitosan (CS) with varying quantities of hydroxyapatite (HA) nanoparticles were developed using a green solution casting method. The formation of blend nanocomposite was confirmed by Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible (UV) spectrometer, field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Mechanical parameters such as tensile strength, percentage elongation at break, hardness, dielectric constant, and temperature-dependent alternating current (AC) conductivity were analyzed. The bonding between the nanoparticles and PVA/CS blend was verified by the shift in distinctive peaks of blend in the nanocomposites to a higher wavenumber in the FTIR spectra. The UV spectra demonstrated the difference in absorbance and transmittance of the PVA/CS blend with the reinforcement of HA nanofillers. The bandgaps of the nanocomposites marginally decreased with an increase in nanoparticle loading. The SEM and XRD patterns revealed the ordered arrangement of the blend matrix due to the presence of nanoparticles. The assessment of thermal characteristics obtained from DSC and TGA demonstrated a clear increase in phase transition temperature and thermal stability of nanocomposites. The electrical conductivity measurement indicated a rise in dielectric constant and AC conductivity of blend nanocomposites with the addition of nanoparticles. The temperature-dependent AC conductivity showed a reduction in activation energy as temperature and nanoparticle loading increased. The tensile strength and surface hardness of the PVA/CS blend nanocomposite increased with the dosage of HA content in the blend matrix.HighlightsA series of polyvinyl alcohol (PVA)/chitosan (CS)/hydroxyapatite (HA) nanocomposites were prepared by the green methodEnhanced optical property, thermal stability, and glass transition temperaturePossess excellent dielectric constant and alternating current conductivityThe inclusion of HA increased the mechanical strength of the PVA/CS blendA potential blend nanocomposite for flexible optoelectronic and charge storage devices. Mechanism of the hydroxyapatite reinforced polyvinyl alcohol/chitosan blend nanocomposites.image