Multifunctional PVA-based materials doped with rare earth chlorides (Eu 3+,Yb 3+ ): Comprehensive thermal,optical,electrical and antibacterial analysis

Abstract

A lanthanide trichloride system, specifically EuCl₃ and YbCl₃, was doped into PVA polymer film using a solution casting technique. The final composite rare earth films were described to examine their physical and structural characteristics. XRD and FT-IR investigations demonstrated significant complexity in the composite films. Thermogravimetric analysis showed that the composite films exhibited a higher residual mass percentage at 500°C compared to pure PVA. According to the UV-Vis, it was observed that pure PVA’s absorption edge and energy gap value decreased with the incorporation of Eu³⁺ and Yb³⁺ ions. The AC conductivity and dielectric constant of the composite rare earth films were analyzed. The 5 wt% (EuCl₃-YbCl₃) doped PVA film displayed the highest dielectric constant, followed by the 5 wt% YbCl₃ and the 5 wt% EuCl₃ films. The same behaviour was observed for AC electrical conductivity, which follows Jonscher’s law. Impedance data concerning the electrical modulus formalism (M*) and impedance formalism (Z*) were analyzed. The relationship between the real and the imaginary components of Z* showed an inclined spike at low frequencies and a semicircular arc at high frequencies, which was fitted to equivalent circuit models. Antibacterial activity was assessed and significantly improved against Klebsiella pneumoniae, a gram-negative bacterium.