Greener synthesis of lightweight, self-standing PMMA/CoFe2O4 polymeric film for magnetic, electronic, and terahertz shielding applications

This work aims to develop a multifunctional PMMA/CoFe2O4 polymeric film of low loss dielectric constant, high magnetic properties, and perceptible terahertz shielding effectiveness. Pure cobalt ferrite magnetic nanoparticles (CoFe2O4 MNPs) were prepared by a facile-modified solution deposition method. Then, the nanoparticles were loaded to poly (methyl methacrylate) of different ratios (x = 0, 5, 10, 15, and 20 wt%) to synthesize films by evaporative casting technique. X-ray diffraction (XRD) evidenced the formation of CoFe2O4 MNPs in the cubic spinal structure. The FTIR confirmed the interaction of CoFe2O4 MNPs with PMMA chains. Compared to the pure PMMA, the PMMA/CoFe2O4 nanocomposites were more thermally stable, as evidenced by thermogravimetric analysis, (TGA) and differential scanning calorimetry (DSC). The micrograph images by FESEM unraveled that CoFe2O4 MNPs have formed in different geometrical shapes (nanocubes, nanotubes, and nano oval). The values of the band gap energy were computed by the absorption spectra fitting (ASF) method. It varied from 4.94 to 4.68 eV, as the CoFe2O4 MNPs contents were changed from 0 to 20 wt%. Compared to host PMMA, the dielectric permittivity was enhanced, while the dielectric loss was slightly decreased. Therefore, the prepared film can be employed as a passive component in electronic circuits, namely capacitors and supercapacitors. The shielding effectiveness (SE) was found to be improved with frequency and CoFe2O4 content, reflecting the applicability of PMMA/CoFe2O4 MNPs films in terahertz shielding. The magnetic parameters were investigated by a vibrating sample magnetometer (VSM) and were found to increase with CoFe2O4 content, which could be used as a flexible film in magnetic applications.