Nematic-like organization of magnetic mesogen-hybridized nanoparticles.

A fluid nematic-like phase is induced in monodisperse iron oxide nanoparticles with a diameter of 3.3 nm. This supramolecular arrangement is governed by the covalent functionalization of the nanoparticle surface with cyanobiphenyl-based ligands as mesogenic promoters. The design and synthesis of these hybrid materials and the study of their mesogenic properties are reported. In addition, the modifications of the magnetic properties of the hybridized nanoparticles are investigated as a function of the different grafted ligands. Owing to the rather large interparticular distances (about 7 nm), the dipolar interaction between nanoparticles is shown to play only a minor role. Conversely, the surface magnetic anisotropy of the particles is significantly affected by the surface derivatization.