Tailoring the Multifunctional Properties of Electrospun PVA/PVP Nanofibers via TiO2 Nanoparticle Doping for Flexible Biomedical and Optoelectronic Applications

This study investigates the impact of TiO2 incorporation (0, 2, 4, 6, 8 wt.%) on the structural, optical, electrical, mechanical, and antibacterial properties of electrospun PVA/PVP nanofibers. FESEM observations revealed continuous, randomly oriented nanofibrous films with an average diameter in the 77–96 nm range, depending on TiO2 content. FTIR and XRD analyses confirmed successful nanoparticle integration, showing effective interfacial interactions and the presence of crystalline TiO2 phases within the semi-crystalline PVA/PVP matrix. Optical studies demonstrated a progressive decrease in the indirect band gap with increasing TiO2 loading, decreasing from 3.75 to 3.54 eV according to the Tauc method and from 3.70 to 3.43 eV according to the ASF method, accompanied by an increase in Urbach energy from 0.43 to 0.64 eV, indicating enhanced structural disorder and tail state formation. The optical dispersion parameters obtained from the Wemple−DiDomenico model were consistent with these trends. Electrical characterization showed enhanced DC conductivity with increasing TiO2 content and a marked reduction in thermal activation energy from 2.54 eV for the neat blend to 0.98 eV at higher TiO2 loading, confirming facilitated charge transport in nanocomposite system. Mechanical characterization indicated that TiO2 reinforcement improved both stiffness and strength, with the 6 wt.% sample achieving an optimal strength–ductility synergy (8.9 MPa and 121.5% elongation). Additionally, TiO2 loading significantly boosted antibacterial performance, particularly against Escherichia coli and Staphylococcus aureus at 8 wt.%. These multifunctional properties position PVA/PVP:TiO2 nanofibers as highly promising candidates for flexible biomedical coatings, optoelectronic devices, and advanced functional surfaces.