Synthesis, Characterization, and Application of Partially\nBlocked Amine-Functionalized Magnetic Nanoparticles

Abstract

In\nthis study, a novel technique was introduced for selective surface\nmodification of amine-functionalized magnetic nanoparticles. The method\nwas based on alignment of magnetic nanoparticles in an external magnetic\nfield, which resulted in formation of chain-like assemblies in diluted\nsuspensions. The aligned chains were then modified on the surface\nvia reaction of isocyanate species with the particle functionalities.\nFinally, after removal from the reactor medium, particles with segmented\ndistribution of surface functionalities were achieved. We named these\npartially blocked amine-functionalized magnetic nanoparticles as “Saturn”\nnanoparticles. Application of the particles in fabrication of magnetic\nassemblies was successfully demonstrated. Using methylene diphenyl\ndiisocyanate (MDI) as the bridging agent, structures in different\nforms such as chains and filaments were produced by the Saturn particles\nand compared with cross-linked structures of the unmodified amine-functionalized\nparticles. It is expected that this novel nanoparticle with its unique\nstructure will have great potential in assembly fabrication with a\nvariety of applications in biomedical fields.