Polymethacrylamide-functionalized graphene oxide via the RAFT method: an efficient fluorescent nanosensor for heavy metals detection in aqueous media

The application and fabrication of graphene-based nanomaterials have recently received great attention in the field of sensors. In this study, a graphene oxide (GO)-based heavy metals nanosensor was prepared via the surface reversible addition-fragmentation chain transfer (RAFT) method. To end this, GO was first prepared from graphene and followed by it was modified with L-phenylalanine (LP). Then, a RAFT agent was attached chemically to the LP-functionalized GO (GO-LP). Finally, GO-LP/polymethacrylamide (GO-LP/PMAM) was prepared via the polymerization of methacrylamide (MAM) monomers on the surface of the GO. The chemical structure and properties of the prepared materials were considered by FT-IR, SEM, TGA, UV, and PL techniques. The results of PL indicated that the GO-LP/PMAM has a higher PL intensity compared to GO and GO-LP spectra in the water. Ultimately, the modified GO was employed as an excellent nanosensor for the selective detection of Cu (II) ions in the range of 0.25-2 mM (R-2 = 0.9903) with a limit of detection (LOD) of 0.19 mM. The absence of any obvious alteration in the fluorescence intensity after the addition of other metal ions indicated the great selectivity for the detection of Cu (II). Based on the experimental results, the surface functionalization of GO with RAFT strategy could be successfully employed as a promising nanosensor for selective detecting of Cu (II) ions.