Covalent functionalization of graphene oxide with polyglycerol and their use as templates for anchoring magnetic nanoparticles

An efficient strategy for the preparation of water-dispersible hybrid material containing graphene oxide and polyglycerol for the first time is demonstrated. Pristine graphite was firstly oxidized to obtain graphene oxide with hydroxyl functional groups. Then, the covalent grafting of polyglycerol onto the surface of graphene oxide was carried out based on in situ ring-opening polymerization of glycidol. For the construction of novel hybrid nanostructure, Fe-core/Au-shell nanoparticles were prepared and further functionalized using 4-mercaptophenylboronic acid through the well-developed Au–S chemistry. Subsequently, magnetic nanoparticles were anchored on the surface of polyglycerol-grafted graphene nanosheets via boroester bonds. The resulting hybrid materials were characterized using a range of analytical techniques. Fourier transform infrared spectroscopy (FT-IR) was employed to investigate the initial changes in surface functionalities. While X-ray diffraction (XRD) was used to confirm the structure of graphene oxide nanosheets, high resolution transmission electron microscopy (HR-TEM), and field emission scanning electronic microscopy (FE-SEM) equipped with an energy dispersive X-ray (EDX) spectrometer were used to study the morphologies and distribution of magnetic nanoparticles onto the surface of polyglycerol-grafted graphene. Thermogravimetric analysis (TGA) was used to study the weight loss of the samples on heating. Superconducting quantum interference device magnetometer (SQUID) was employed to the magnetic property of magnetic nanoparticles. The digital images provided a vivid observation on the high dispersion stability of the prepared novel hybrid materials in distilled water.