Does the self-assembled coating of magnetic nanoparticles cover individualparticles or agglomerates?

Communication: Monolayer coatings on magnetic nanoparticles are of special interest because of their important technological applications in electroni cs, magnetic recording, magnetic fluids, etc. The surfactant coating acts a s a stabilizer and is believed to prevent agglomeration. In this study the authors show that the self-assembly of the monolayer coating takes place on the surface of agglomerates, rather than on the surface of separate nanopa rticles. This result is confirmed by elemental analysis and surface area an d magnetic measurements of samples with different chain lengths of the surf actant molecule.