Langmuir Monolayers of Monodispersed Magnetic Nanoparticles Coated with a Surfactant

Monolayers of hydrophobic magnetic nanoparticles are deposited on a water subphase in a Langmuir trough. The shape of the surface isotherms and the electron-micrograph pictures appear to be strongly dependent on the particle size. Small particles are organized in more compact aggregates than larger ones. We interpret this behavior as a size-dependent balance between van der Waals and magnetic interparticle interactions.