Formation of Chitosan/Sodium Phytate/Nano-Fe3O4 Magnetic Coatings on Wood Surfaces via Layer-by-Layer Self-Assembly

Magnetic wood would have potential uses in electromagnetic shielding and electromagnetic wave absorption. In this paper, magnetic coatings on a wood surface were synthesized using a layer-by-layer self-assembly method. As the cationic polyelectrolyte carrier, natural macromolecular chitosan was pre-immobilized on a wood surface first, followed by the alternate adsorption of anionic polyelectrolyte sodium phytate and positively-charged Fe3O4 nanoparticles. The concentration of pH-controlled chitosan solution, sodium phytate solution, and Fe3O4 nanoparticle suspension, soaking time, and the number of alternating sedimentary layers varied. The morphology and crystal structure of the Fe3O4 modified wood samples were studied using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The magnetic hysteresis loops showed that the modified wood had magnetic properties which were improved as the number of assembled layers increased.