Polymerization of monomer-based ferrofluids.

Ferrofluids based on oleate-stabilized nanoparticulate magnetite in cyclic olefin carrier solvents were prepared. Puddles of fluids containing 20-70 wt % magnetite in 1,5-cyclooctadiene or dicyclopentadiene can be moved or positioned on surfaces or in vessels with moderate magnetic fields (inexpensive NdFeB magnets). The surfaces of puddles with concentrations >40 wt % distort in response to magnetic fields applied perpendicular to the puddle surface and exhibit pointed liquid asperities. The liquid surface topography (asperity height and number per unit area) can be controlled by the strength of the applied field. The cyclic olefin carriers can be polymerized by ring-opening metathesis, solidifying the ferrofluid samples in the shape of the magnetically distorted monomeric solvent suspensions.