Xuesong Jiang

Responsive Polymer Nanoparticles Formed by Poly(ether amine) Containing Coumarin Units and a Poly(ethylene oxide) Short Chain

We reported a novel poly(ether amine) (PEAC) containing poly(ethylene oxide) (PEO) short blocks and coumarin units, which was synthesized by nucleophilic addition/ring-opening polymerization of diepoxy and diamine monomers. PEAC can be directly dispersed in aqueous solution as uniformly sized nanoparticles 50-60 nm in diameter. The whole process for aggregation of PEAC was revealed by transmission electron microscopy (TEM) and ultraviolet-visible (UV-vis) spectra. The results show that these polymeric nanoparticles possess a very sharp response to temperature and light, and can form complex micromicelles with nanoparticles inside.

High performance carbon molecular sieving membranes derived from pyrolysis of metal–organic framework ZIF-108 doped polyimide matrices

Carbon molecular sieve membranes (CMSMs) were fabricated by pyrolysis of MOF-doped polyimide mixed matrix membranes. ZIF-108 (Zn(2-nitroimidazolate)2) was used as a dopant to tailor the micropores of the as-prepared CMSMs into narrow ultramicropores, providing a remarkable combination of permeability and selectivity of membranes in CO2/CH4, O2/N2 and N2/CH4 separation.

Thiol–ene photo-curable hybrid silicone resin for LED encapsulation: enhancement of light extraction efficiency by facile self-keeping hemisphere coating

Encapsulation with polymer materials can not only protect LED chips, but also enhance light extraction efficiency (LEE), and thus it has become necessary for the fabrication of LED devices. We developed a new concept of LED encapsulation with photo-curable hybrid silicone resin, which allows facile encapsulation at room temperature. The photo-curable silicone liquid resin based on thiol–ene photopolymerization is comprised of styrene-modified mercaptopropyl-polysilsesquioxane (St-POSS-SH) with a ladder-like polysilsesquioxane containing acrylic and phenethyl sulfide groups (LPSQ). Even under open air condition, the resulting liquid silicone resin can be photo-cured in 2 minutes at room temperature, and can keep a hemisphere shape during encapsulation without a mold. The optical, mechanical and thermal properties of the resulting cured silicone resin were evaluated in detail. The silicone resin is transparent and possesses a high refractive index of 1.545(@450 nm). The encapsulation of blue GaN LED with this self-keeping hemisphere-shaped photo-cured silicone resin achieved a LEE enhancement of 25.6%, compared to flat encapsulation induced by heat. Contrary to thermal encapsulation, the encapsulation of an LED chip with the photo-curable silicone resin does not involve the processes of mold and demold, which simplifies the LED encapsulation procedure, and obviously decreases the operation cost. We believe that this novel photo-curable silicone resin based on thiol–ene photopolymerization will greatly improve the encapsulation of LED chips.

Photoinitiated synthesis of polymer brush from dendritic photoinitiator electrostatic self-assembly

We report on a simple and effective method to prepare polymer brush by electrostatic self-assembly of dendritic macrophotoinitiator and photoinitiated polymerization.