A multifunctional PANI–chitosan–TiO₂ nanocomposite: Bridging photocatalysis, anticorrosion, and biomedical applications

PCT (Polyaniline, Chitosan, and TiO 2 ) nanocomposites (NCs) were synthesized via oxidative polymerization for multifunctional applications. Structural properties of NCs were investigated using UV–visible, FTIR, SEM-EDX, and X-ray diffraction studies. Photocatalytic degradation of organic dyes, Crystal violet (98.2%), Methylene blue (96.5%), Methyl orange (92.0%), and Rhodamine-B (97.3%) were investigated in UV light. The synthesized NCs exhibit 83.78% corrosion inhibition efficiency in 1.0 N H 2 SO 4 at 100 ppm concentration. MD simulation study supports experimental corrosion results and demonstrates strong chemisorption of PCT NCs on the Fe (110) surface. The NCs were found to be paramagnetic (χ = 0.071), and the induced current increased with increasing applied magnetic field. The optical band gap in the PCT ternary NCs decreased from 3.2 eV for TiO 2 and 3.88 eV for PANI to 2.8 eV. S. aureus , a Gram-positive type, and E. coli , a Gram-negative type, were used to check the zone of inhibition, i.e., (18.5 ± 0.8 mm and 16.2 ± 0.5 mm), respectively, at 15 mg NCs, and found comparable to the standard antibiotic (Ampicillin), with no antifungal effect. The synthesized NCs showed anti-inflammatory properties with an IC50 of 8.33 ± 0.10 µM. The NCs showed antioxidant activity as assessed by DPPH, radical scavenging assay, with an IC50 value of 3.32 ± 0.11 µM. An excessive degree of antimalarial effect was achieved by NCs upon interacting with the strain of Plasmodium falciparum 3D7, with an IC50 value of 3.28 ± 0.14 µM. PCT NCs have potential uses in environmental remediation and wastewater treatment. The multi-functionality of NCs opens new pathways for their use in biomedical, anticorrosive, magnetic, and environmental fields.