Magnetic Cu0.5Co0.5Fe2O4 ferrite nanoparticles immobilized in situ on the surfaces of cellulose nanocrystals

A novel magnetic cellulose nanocrystal material decorated with Cu-Co ferrite was synthesized in situ by controlled hydrothermal chemistry in the presence of NH3 center dot H2O. The ferrite nanoparticles immobilized on cellulose were found to exist in their oxide forms as identified by FTIR, XPS and Raman spectra. They demonstrate very good dispersibility with smaller crystal size after being formed in situ on the surface of a nanocellulose crystal template by the application of ammonia. The crystalline structure of cellulose can only be maintained at relatively low contents of ferrite surface decoration (11.0 %) versus high contents (e.g., 75.6 %). Moreover, the magnetic properties of the resultant materials could be controlled by changing the ratio of the molecular components in the ferrites. At the low ferrite contents, the composition was Cu0.5Co0.5Fe2O4 at a small crystal size of 13.5 nm that provided a maximum saturation magnetization of 10.95 emu/g. Finally, the thermostability of the nanocomposite was improved after immobilizing the magnetic nanoparticles.