关键词: 复合纳米材料, Fe₃O₄纳米粒子, 化学发光, 纳米通道

The design and synthesis of functional nanocomposites are very important since these materials have been widely used in different fields such as catalytic chemical reaction, the fabrication of chemical sensors or biosensor as well as the design of the nanodrug delivery systems. Herein, a new method for preparing the Chitosan/Fe₃O₄/SiO₂ magnetic nanocomposites by the reverse microemulsion route was developed. The magnetic fluid, which was consisted of the chitosan and Fe₃O₄ nanoparticles, was firstly prepared based on the strong supra-molecules interaction between chitosan and Fe₃O₄ nanoparticles. Then, due to the better and stronger affinity of the silica to chitosan, the chitosan modified magnetic fluids was successfully doped into the silica nanoparticles while the silica nanoparticles was being formed in the reverse microemulsion system. In this case, the magnetic chitosan/Fe₃O₄/SiO₂ nanocomposites was successfully synthesized. Thereafter, the magnetic nanocomposites were characterized by transmission electron microscopy (TEM), magnetization curve, SEM energy spectrum, X-ray diffraction (XRD) and zeta potential of the nanoparticles surface techniques, respectively. Our results showed that the as-prepared Chitosan/Fe₃O₄/SiO₂ magnetic nanocomposites were spherical shape with core-shell structure apparently and their size is about 60 nm. More importantly, it was also found that there were lots of nanochannels inside the as-prepared Chitosan/Fe₃O₄/SiO₂ magnetic nanocomposites due to the porous hydrogel structural property of the chitosan. At the same time, the nanochannel behavior of the nanocomposites was further investigated by using the Luminol-H₂O₂ chemiluminescence reaction based on the catalytic effect of magnetic Fe₃O₄ particles towards the chemiluminescence reaction. The chemiluminescence investigating results showed that the 60 nm Chitosan/Fe₃O₄/SiO₂ magnetic nanocomposites offered a lot of nanochannels, which allowed both the luminol and H₂O₂ to be diffused into the inner part of the nanocomposites to react with Fe₃O₄ particles in the core part of the nanocomposites and produce the catalytic chemiluminescence signals. This behavior of the as-prepared magnetic nanocomposites may pave way to design the chemiluminescence-based sensor or biosensor.

Key words: nanocomposites, Fe₃O₄ nanoparticles, chemiluminescence, nanochannel