Directed synthesis of molecularly braided magnetic nanoparticle chains using polyelectrolyte and difunctional couplers

A synthesis approach for creating magnetic nanoparticles chains of FePt or Fe₃O₄, with controllable dimensions and aspect ratio by direct growth and molecular braiding of nanoparticles has been presented. FePt nanoparticle chains were synthesized by refluxing platinum acetylacetonate Pt(acac)₂ and iron acetylacetonate Fe(acac)₃, in pentandiol in the presence of polyethelenimine (PEI), a cationic polyelectrolyte, and succinic acid (SA), a dibinding surfactant. Both PEI and SA were found important factors that determine the size and morphology of the nanostructures. The as-prepared FePt and Fe₃O₄ nanoparticles chains were found to be superparamagnetic. The approach can be extended to obtain nanostructures of other elemental and intermetallic alloy materials that are difficult to synthesize and assemble by conventional solvothermal or surfactant-directed methods.