Synthesis and characterization of polyaniline composite incorporated with TiO2 nanoparticles for enhancement of antibacterial activity

Abstract

In this study, pristine polyaniline (PANI) and PANI–TiO₂ nanocomposites containing different amounts of TiO₂ were synthesized by chemical oxidative polymerization using aniline as the monomer and ammonium persulfate as the oxidizing agent. The structural, functional and optical properties of the prepared materials were investigated using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and UV–visible spectroscopy. XRD confirmed the presence of crystalline anatase TiO₂ within the semicrystalline PANI matrix, while FTIR indicated interfacial interactions between PANI functional groups and TiO₂ surface sites. UV–visible analysis showed a gradual change in the optical response with increasing TiO₂ content. The antibacterial activity was evaluated against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli using the agar disc-diffusion method. Among the investigated PANI–TiO₂ composites, the PT5 sample exhibited the largest observed inhibition-zone diameters under the experimental conditions used. Because the antibacterial measurements were obtained from a single experimental determination for each sample, the reported inhibition zones are treated as comparative observations rather than statistically validated mean values. The results demonstrate that TiO₂ incorporation modifies the structural, spectroscopic and antibacterial characteristics of PANI, with the response depending on TiO₂ loading.