Aqueous solutions containing a mixture of polyethylene glycol (PEG) and dextran homopolymers form an aqueous two-phase system which can be emulsified to give a water-in-water emulsion. We show how these emulsions can be stabilized using triblock polymers containing poly[poly(ethylene glycol) methyl ether methacrylate] (PEGMA), poly (n-butyl methacrylate) (BuMA), and poly[2-(dimethylamino) ethyl methacrylate] (DMAEMA) blocks of general structure Pp-Bb-Dd, in which the middle BuMA block is hydrophobic. Low-energy input stirring of mixtures containing equal volumes of PEG- and dex-rich aqueous phases plus 1 wt % of Pp-Bb-Dd stabilizer all form dex-in-PEG emulsions (for the range of Pp-Bb-Dd triblock polymers used here) which have a polymersome-like structure. In favorable cases, the emulsion drop (or templated polymersome) sizes are a few micrometers and are stable for periods in excess of 6 months. The emulsions can be inverted from dex-in-PEG to PEG-in-dex by increasing the volume fraction of dex-rich aqueous phase. We demonstrate that both high and low molecular weight fluorescent solutes "self-load" into either the dex- or PEG-rich regions and that solute mass transfer across the water-water interface occurs on a timescale of less than 1 min.

Metal coordination polymer nanoboxes are reported for the first time. Initially spherical miniemulsion droplet templates were transformed to hollow cubic crystalline nanostructures via a miniemulsion periphery polymerization conducted under benign thermal and chemical conditions.

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 Fe(3+) 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 Fe(3+) 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.

We fabricated PPy/PB core/shell nanoparticles via one-step miniemulsion polymerization using a metallosurfactant of EPE-Fe. The defined hollow structure endows PB nanoshells with an emission band at 612 nm. On incorporating PPy inside PB shells, a blue shift and enhanced fluorescence were observed due to charge transfer from PPy to PB.

Prussian Blue (PB) analogue metal coordination nanocages comprised of mesoporous walls (ca. 3.5 nm pore width) encapsulating a cavity approaching ca. 100 nm in diameter (surfactant free) are presented as an advance in rational metal coordination polymer nanostructure design. The synthesis employs lanthanide ions (Gd(3+) or Er(3+)) which function initially as peripheral coordination crosslinkers of metallo-surfactant templated miniemulsion droplets, and, subsequently, as promoters in the removal of the organic component of those surfactants via metal-assisted ester hydrolysis. The success of this synthetic strategy relies entirely on the periphery coordination event occurring prior to the ester hydrolysis surfactant removal step. Crucially, this one-pot sequential synthesis was achieved using a newly developed metallo-surfactant designed to have a reduced ester hydrolysis rate. Syntheses of this innovative metallo-surfactant, intermediary PB analogue coordination polymer organo-nanoshells and the subsequent conversion to hollow metal coordination nanocages are fully characterised using a wide variety of techniques, including TEM, SEM, EFTEM, EDX, TGA, WAXD, NMR, N(2) adsorption, etc., and represent the first designed synthesis of hollow metal coordination nanocages containing a large nanoscale cavity (wall of hollow nanosphere is mesoporous; hence nanocage).