Self-Assembly of Cobalt Nanoparticle Rings

Abstract

Weakly ferromagnetic cobalt nanoparticles can assemble spontaneously into nanosized "bracelets" when dispersed in organic solvents containing resorcinarenes as surfactants. Bracelet self-assembly occurs in solution and is directed by magnetic dipolar interactions, whereas nanoparticle rings with larger diameters are produced by evaporation-driven flow on wetted surfaces.