Abstract

Self-assembly of magnetic nanoparticles into a long-range monolayer pattern is under investigation in both theoretical aspect and data storage application. In this work, the effect of liquid and solid substrates on the nanoparticle assembly was compared. Iron (III) dibenzoylmethane (Fe(dbm) <inf>3</inf> ) was used as an alternative reagent to highly toxic iron pentacabonyl (Fe(CO) <inf>5</inf> ) in the co-reduction with platinum acetylacetonate (Pt(acac) <inf>2</inf> ). The as-synthesized iron-platinum (FePt) based nanoparticles were dropped either on diethelyne glycol (DEG) or directly on carbon-coated copper grid. In the case of DEG, the drastic movement of nanoparticles during the liquid-air interface assembly tracked by a camera terminated after 15 seconds. A subsequent inspection after transferring the monolayers from DEG to carbon-coated copper grid grid substrates confirmed the extended area of ordered nanoparticles from the liquid-air interface assembly. These results demonstrated that the liquid-air interface method is effective not only in patterning monodisperse nanoparticles but also those with wider size distributions.