Innovative magnetic tri-layered nanocomposites based on polyxanthone triazole, polypyrrole and iron oxide: synthesis, characterization and investigation of the biological activities

Abstract

A magnetic multi-functional composite with a tri-layer core–shell–shell construction was successfully prepared by a combination process involving click reactions and emulsion polymerization. Firstly, magnetic polyxanthone triazole (PXT) was synthesized via the click reaction of bisethynyl and 2,7-(N-2-chloroacetamide) xanthone (NClX) in the presence of Fe₃O₄ nanoparticles. Then, a polypyrrole@polyxanthone triazole@Fe₃O₄ (PPy@PXT@Fe₃O₄) tri-layered nanocomposite was prepared via emulsion polymerization of pyrrole in the presence of magnetic PXT using sodium dodecyl sulfate (SDS) as an emulsifier and ammonium persulfate (APS) as an oxidant. Characterization of the synthesized polymer and nanocomposite was carried out by nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) survey, transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) studies. Also, the antioxidant activity of the nanocomposites was examined and compared with the bare polymer using a 2,2-diphenyl-1-picryl-hydrazyl free radical (DPPH˙) assay. In addition, the in vitro antibacterial activities of the di-layered and tri-layered nanocomposites were studied by inhibition zone methods. The results showed a greater synergic effect in the thermal stability, antioxidant and antibacterial activities of the tri-layered nanocomposite than of the di-layered nanocomposite. Thus, the developed PPy@PXT@Fe₃O₄ tri-layered nanocomposite could be used effectively for biomedical applications and would be a good sorbent candidate for the microbial treatment of wastewater.