Selective Growth of Cobalt Nanoclusters in Domains of Block Copolymer Films

We have produced, by thermal decomposition of an organometallic complex in a bulk film of P(S- b -2VP), nonagglomerated cobalt nanoparticles that exhibit significant room-temperature magnetic coercivity. The particles are patterned on the nanoscale: they reside within the P2VP domains of the block copolymer morphology. These results are made possible by the selective sequestration of the organometallic complex into these domains in amounts sufficient to nucleate and grow substantial quantities of cobalt nanoparticles that are larger than the size required for ferromagnetic behavior. The in situ synthesis of ferromagnetic nanoparticles selectively inside the P2VP domains of P(S- b -2VP) block copolymer films has been demonstrated.