Ultrasound Synthesis of Polyindole–TiO2 Nanocomposite and Evaluation of Antibacterial Activity

The present work reports the synthesis and evaluation of antimicrobial activity of polyindole–TiO2 nanocomposite. Polyindole–TiO2 nanocomposite was synthesized by aqueous in situ chemical polymerization of indole using ammonium persulfate as an oxidant under ultrasonic condition. The synthesized polyindole and polyindole–TiO2 nanocomposites were characterized by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscope, thermogravimetric analysis, and X-ray diffraction techniques. A sharp peak at ∼1,402 cm−1 is due to the stretching vibrations of O‒Ti‒O bond in polyindole–TiO2 nanocomposite. The X-ray diffraction pattern shows the major diffraction peaks at 25°C and 48°C, indicating TiO2 in anatase form. Polyindole–TiO2 shows maximum activity against gram-positive Staphylococcus aureus and Bacillus subtilis as compared to gram-negative Escherichia coli.