Lixia Bao

Synthesis, characterization, and self-assembly behaviors of a biodegradable and anti-clotting poly(EDTA-diol-co-butylene adipate glycol urethanes)

Anti-clotting EDTA-diol was successfully synthesized by an esterification reaction between EDTA-2Na and poly(ethylene glycol). Novel anti-clotting and biodegradable multi-block polyurethanes were then prepared by EDTA-diol and biodegradable poly(1,4-butylene adipate glycol) (PBA) as the soft chain, and 1,4-butanediol (BDO) and hexamethylene diisocyanate (HDI) as the hard chain, respectively. The effect of the EDTA-diol content in the soft chain of the prepared polyurethanes on mechanical properties, thermal stability, hydrophilicity, and anticoagulant ability was largely investigated by tensile tests, thermogravimetric analysis, contact angle and water absorption measurements, and hemolytic measurement. Self-assembly behaviors of the resulting polyurethanes were also evaluated by fluorescence spectroscopy and transmission electron microscopy. The prepared polyurethanes have large potential applications in the fields of biomedical materials such as tissue engineering and drug carriers.

Real-time tracking the Li + -ion transition behavior and dynamics in solid Poly(vinyl alcohol)/LiClO 4 electrolytes

To delicately track the Li-ion transport in SPEs under an external electric field (EF) is a big challenge, considering the limitation of most spectroscopic methods to monitor the real-time conformational changes and track the dynamic process. Herein, real-time Li-ion transition behavior and transport dynamics in typical poly(vinyl alcohol)/LiClO4 electrolytes under an external EF have been studied by combining time-resolved Fourier transform infrared (FTIR) with two-dimensional correlation FTIR spectroscopy. Results show that no migration of Li-ions has been detected when the time scale of the EF loading is at nanosecond (less than 200 ns). However, for the first time, Li-ions have been found to significantly transfer along the EF direction as the time scale enhances to microsecond order of magnitude and the migration period is less than 10 microseconds. The Li+ migration in the SPEs under an EF is a complicated process including quasi-periodic dissociation and coordination effects between Li-ion carriers and polymeric chains.

Investigations on biodegradable polyurethane nanomaterials with different EDTA-diol content in the soft chain

Novel biodegradable multi-block polyurethanes have been prepared by using EDTA-diol and poly(1,4-butylene adipate glycol) (PBA) as the soft chain, and 1,4-butanediol and hexamethylene diisocyanate as the hard chain. The resulting amphiphilic PUs can self assemble in water to form uniform nanospheres or nanotubes. The effect of both the EDTA-diol content in the soft chain and the hard chain content of the prepared PUs on the morphology of the nanospheres or nanotubes is extensively investigated by means of fluorescence spectrometer and transmission electron microscopy. The results show that the morphology of the PU nanoarchitectures can be facilely controlled by changing the EDTA-diol content in the soft chain or the hard-chain content of the PUs. The PU nanoarchitectures gradually change from nanospheres to concentric circle-like ultrafine nanotube aggregates with an inner diameter of 8–12 nm and then to separate ultrafine nanotubes with similar inner diameters when the EDTA-diol content in the soft chain increases from 5 to 50 wt%, attributed to the enhancement of the hydrophilicity of the PUs. The prepared PUs have large potential application in the fields of drug delivery and control release, nanoreactors, and nanocatalysts.

Monodispersed hollow polymer/iron eutectic nanospheres

Oleic acid capped Fe3O4 nanoparticles with a size range of 8–15 nm were prepared by a typical reduction method. Double bonds in the oleic acid molecules were activated and further grafted with methyl methacrylate (MMA) and hydroxyethyl acrylate (HEA) in butyl acetate to obtain acrylate copolymer-coated Fe3O4 nanoparticles. Hexamethylene diisocyanate (HDI) was used as the cross-linking agent to immobilize the surface structure of the nanoparticles. Fe3O4 templates were then disposed of with excessive concentrated HCl solution, and monodispersed ultra-fine and an ultra-light hollow polymer/iron eutectic system with a size range of 18–30 nm was thus obtained. The molecular structures, crystal information, thermal properties, and morphology of the prepared nano-particles were characterized. The results showed that the hollow nanoparticles were composed of an amorphous outer layer and a crystalline inner layer, and that the outer layer and the inner layer mainly consisted of acrylate copolymers and ordered iron oxide atoms, respectively. The cross-linked macromolecular architectures and the chemical bond between Fe atoms and polymeric chains are the main driving force to form such a hollow eutectic system that has never been reported previously. The preparation method reported in this paper firstly develops a route to synthesize hollow polymer/metal eutectic materials, and these hollow nanoparticles have large potential application in the fields of nanoreactors and catalysts.