Synthesis of Prussian Blue Coordination Polymer Nanocubes via Confinement of the Polymerization Field Using Miniemulsion Periphery Polymerization (MEPP)

Miniemulsion periphery polymerization (MEPP) has been used for the synthesis of Prussian blue (PB) nanocubes. Pentacyano ferrate functionalized surfactant in combination with a co-surfactant containing 4-(dimethylamino)-pyridine (DMAP) or OH end groups in lieu of ferrate functionality (EPE-DMAP or EPE-OH) were used to prepare a miniemulsion system comprising 20 wt.-% toluene and 0.5 wt.-% total surfactant. On addition of Fe3+ to the miniemulsion, metal coordination polymerization occurred with nanocubes generated when the ratio of EPE-Fe:EPE-DMAP (or EPE-OH) was 60:40 (w/w). The resulting nanocubes are apparently amorphous. Particles with irregular shape have been observed on reacting EPE-Fe and Fe3+ directly in water, thus suggesting that confinement of the polymerization field on the periphery of the miniemulsion droplets is a primary factor in the formation of cubic structures.