Amphiphilic nanocapsules entangled with organometallic coordination polymers for controlled cargo release.

A class of new amphiphilic nanocapsules entangled with organometallic coordination polymers has been developed for the first time. Poly(2-(N,N-dimethyl amino)ethyl methacrylate)-b-polystyrene capped with ß-cyclodextrin (ß-CD) (CD-PDMAEMA-b-PS) is first synthesized using sequent RAFT polymerization of styrene and 2-(N,N-dimethyl amino)ethyl methacrylate with xanthate modified ß-CD as chain transfer agent. The end group of ß-CD is allowed to include 4,4'-bipyridine through host-guest inclusion to yield PDMAEMA-b-PS terminated with an inclusion complex of ß-CD and bipyridine (bpy-PDMAEMA-b-PS), which is then used as surfactant to prepare emulsion droplets in toluene/water mixture. Upon addition of Ni(II), bipyridine coordinates with Ni(II) to form coordination polymers in the periphery of emulsion droplets, affording amphiphilic capsules entangled with organometallic coordination polymers, as confirmed by GPC, (1)H NMR, SEM, TEM, DLS, and so on. The organometallic coordination polymer capsules are capable of encapsulating organic cargoes. Interestingly, encapsulated cargoes can be extracted from the capsules without damaging the capsules. Such capsules are potential candidates for encapsulating and controlled release of organic cargoes.

Synthesis and characterization of nanowire coils of organometallic coordination polymers for controlled cargo release.

Nanowire coils of organometallic coordination polymers have been synthesized for the first time by using the emulsion periphery polymerization technique. An amphiphilic triblock copolymer terminated with inclusion complex of ß-cyclodextrin and 4,4'-bipyridine self-assembles into oil-in-water emulsion in a toluene/water mixture. Subsequent coordination of bipyridine with Ni(II) in periphery of emulsions results in the formation of coordination polymer nanowire coils. The nanowire coils are composed of nanowires with diameter of 2 nm. Nanowire coils exhibit enhanced thermal stability in contrast to their parent triblock copolymer. Interestingly, nanowire coils are capable of encapsulating organic cargoes. Encapsulated cargoes can be selectively extracted from nanowire coils without damaging nanowire coils. Nanowire coils are potential candidates for encapsulating and controlled release of organic cargoes.

Synthesis and characterization of ultrathin metal coordination Prussian blue nanoribbons.

Ultrathin metal coordination Prussian blue (PB) nanoribbons with tunable width have been successfully synthesized. The morphology and microstructure of PB nanoribbons are characterized using UV-vis, FT-IR, AFM, TEM and XRD. PB nanoribbons synthesized possess an ultrathin thickness of approximately 1 nm and narrow width. The width of PB ribbons can be tuned by varying the chain length of polymeric precursors. The PB hybrid nanoribbons synthesized exhibit enhanced thermal stability and electrochemical activity. The merit of narrow and tunable width as well as ultrathin thickness of PB hybrid nanoribbons along with enhanced thermal stability and electrochemical activity makes them potentially useful in nano-devices, biosensors and so on.

Reversible mechanochromism of a luminescent elastomer.

A novel mechanochromic elastomer was manufactured by doping bis(benzoxazolyl)stibene (BBS) into a thermoplastic polyurethane. Both solution casting and melt compounding approaches were tried with a range of BBS concentrations, and an optimal concentration of 0.5% was selected to investigate the mechanochromic mechanism in detail. When the blend film was stretched up to 100%, its emission peaks at 475 and 413 nm changed in intensity ratio from 6.3 to 1.8. When it was released, both the film size and emission peaks largely recovered. By a short annealing at 120 °C, their full recovery was achieved. Its reversion mechanism was proposed and proved by X-ray diffraction. In comparison to previous mechanochromic materials, this smart elastomer is easy to prepare, highly sensitive to stress, facilely renewable in usage, and totally based on biocompatible materials, having potential applications like stress sensors, intelligent devices, and alarming packages.