Innovative magnetic tri-layered nanocomposites based on polyxanthone triazole, polypyrrole and iron oxide: synthesis, characterization and investigation of the biological activities Vahid Hasantabar, a Moslem Mansour Lakouraj, * a Ehsan Nazarzadeh Zare a and Mojtaba Mohseni b A magnetic multi-functional composite with a tri-layer coreshellshell 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 Fe 3 O 4 nanoparticles. Then, a polypyrrole@polyxanthone triazole@Fe 3 O 4 (PPy@PXT@Fe 3 O 4 ) tri-layered nanocomposite was prepared via emulsion polymerization of pyrrole in the presence of magnetic PXT using sodium dodecyl sulfate (SDS) as an emulsier 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 diraction (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), BrunauerEmmettTeller (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 (DPPHc) 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 eect in the thermal stability, antioxidant and antibacterial activities of the tri-layered nanocomposite than of the di-layered nanocomposite. Thus, the developed PPy@PXT@Fe 3 O 4 tri-layered nanocomposite could be used eectively for biomedical applications and would be a good sorbent candidate for the microbial treatment of wastewater. 1. Introduction In recent years, layered nanocomposites have signied a class of multifunctional materials that has received growing atten- tion. 17 The specic construction of these composites produces a synergistic eect between the organic and inorganic frag- ments, producing compounds with dierent chemical or physical properties as compared to the individual components. Layered nanocomposites not only represent an innovative alternative to the search for new materials, but also allow for the development of pioneering industrial applications. These nanocomposites can be used in intelligent membranes, sepa- ration and photovoltaic devices, fuel cells, catalysis, chemical and biochemical sensors, and medicine. 814 A great variety of layered nanocomposites can be prepared from the combination of polymers and inorganic particles. Among polymer based materials, conductive polymers have been used as an excellent material for the preparation of nanocomposites with specic properties, including their remarkable electronic, magnetic, biological and optical prop- erties. Polypyrrole (PPy) is one of the conductive polymers which has good biological activities (antibacterial, antioxidant, and anti-cytotoxicity) and good physical properties. 1519 To the best of our knowledge, magnetic polymer composites, as an illustrative example of multifunctional composites, are receiving more attention because of their peculiar structure and properties. 2023 They have found a wide number of applications in various elds such as biomedicine and bioengineering. So far many researchers have reported multifunctional composites, for instance Gok and co-workers synthesized a PT/PS/SiO 2 nanocomposite in a nonaqueous medium by a chemical method. 24 Kong and co-workers have reported a multifunctional multi-walled carbon nanotube/Fe 3 O 4 nanoparticle/polyaniline composite as an electromagnetic composite. 25 Li and co- a Department of Organic-Polymer Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran, 47416. E-mail: lakouraj@umz.ac.ir; Fax: +98 1135342350; Tel: +98 1135242354 b Department of Microbiology, Faculty of Basic Science, University of Mazandaran, Babolsar, Iran, 47416 Cite this: RSC Adv. , 2015, 5, 70186 Received 22nd April 2015 Accepted 5th August 2015 DOI: 10.1039/c5ra07309j www.rsc.org/advances 70186 | RSC Adv. , 2015, 5, 7018670196 This journal is © The Royal Society of Chemistry 2015 RSC Advances PAPER