Synthesis, structural characterization and effect of surface modification on magnetization of hybrid manganese ferrite nanoparticle

Abstract Paramagnetic Poly-methyl methacrylate (PMMA) and Poly ethylene glycol (PEG) functionalized manganese ferrite (PMMA-PEG-MF) nanoparticles were synthesized through a facile and efficient method. The resulting nanoparticles (NPs) were characterized using PSA, EDX, FT-IR, TEM, XRD, SEM, TGA and VSM techniques. The PMMA-PEG-MF NPs were nanocrystalline and depicted plate like particles with a mean size of around 70 nm as compared to the size of the MnFe2O4 nanoparticles which was observed to be 66 nm. The EDX validated the existence of metal ions and the modifiers (polymethylmethacrylate and polyethylene glycol) in the NPs. The FTIR confirmed the functionalization of MnFe2O4 NPs with PMMA and PEG. The XRD studies revealed that the synthesized MF and PMMA-PEG-MF NPs were crystalline and had a cubic spinel structure with a crystallite size of 14.64 nm and 14.42 nm and lattice parameter was calculated to be 6.20 Å and 3.90 Å respectively. The SEM micrograph revealed highly agglomerated nanostructures in the MnFe2O4 NPs; however, the extent of agglomeration reduced significantly post modification with PMMA and PEG. The TGA study exhibited an overall weight loss of 2.86% and 25.11% for MnFe2O4 and PMMA-PEG-MF NPs respectively. Magnetization measurements showed a substantial reduction in the saturation magnetization (Ms) and magnetic moment (µB) after modifying MnFe2O4 with PMMA and PEG. A saturation magnetization of 0.0056 emu/g was derived for PMMA and PEG modified MnFe2O4 NPs, as compared to 23 emu/g for MnFe2O4 magnetic NPs, suggesting paramagnetic behaviour of the synthesized NPs.