Poly(styrene-acrylonitrile) emulsion particles with positive charges on the surface were synthesized by emulsion polymerization using cationic surfactant octotyltrimethyl ammonium chloride (OTAC) as emulsifier.The sus...Poly(styrene-acrylonitrile) emulsion particles with positive charges on the surface were synthesized by emulsion polymerization using cationic surfactant octotyltrimethyl ammonium chloride (OTAC) as emulsifier.The suspension of montmorillonite was slowly dropped into the emulsion.Through the interaction between the negative charges on the montmorillonite layers and the cations on the surface of poly(styrene-acrylonitrile) particles, the montmorillonite layers and emulsion particles could assemble and absorb on each other by themselves.The change of δ voltage and particle size of the emulsion during the process of dropping was characterized, which demonstrated that the emulsion particles and montmorillonite layers absorbed on each other by the electrovalent bond and an intersectional structure was formed in the complex emulsion.Poly(styrene-acrylonitrile)/ montmorillonite nanocomposite was obtained after coagulation.The structure of nanocomposite was characterized with XRD and TEM.The results indicated that montmorillonite was exfoliated into layers with a thickness of several nanometers and uniformly dispersed in the polymer matrix.展开更多
Polystyrene （PS） @SiO2 core-shell microbeads with large pore and large particle size were prepared via layer-by-layer（LBL）assembly technique for potential applications in nano-micro composites. Negative silica nan...Polystyrene （PS） @SiO2 core-shell microbeads with large pore and large particle size were prepared via layer-by-layer（LBL）assembly technique for potential applications in nano-micro composites. Negative silica nanoparticles synthesized via modified St6ber method and cationic poly （diallyldimethylammonium chloride） were alternately adsorbed on the surface of microbeads. Zeta potential, size, and morphology of the microbeads were monitored during LBL assembly process to ensure the successful deposition of silica nanoparticles. The porous shell was characterized using nitrogen adsorption and desorption analyses, and the surface area, volume and diame- ter of the pores were derived. It is found that the porous shell thickness and the pore size can be tuned by changing the coating times of silica nanoparticles. Finally, PS@SiO2 core-shell microbeads with 5 grn PS solid core and 350 nm mesoporous shell （mean BJH pore diameter is ~27 nm） were used to load CdSe/ZnS quantum dots （QDs）. The fluorescence microscopic image and the optical amplification of the QDs-embedded microbeads （QDBs） indicate that the as-prepared core-shell microbeads can provide adequate space for QDs and may be useful for further application of nano-micro composites.展开更多
文摘Poly(styrene-acrylonitrile) emulsion particles with positive charges on the surface were synthesized by emulsion polymerization using cationic surfactant octotyltrimethyl ammonium chloride (OTAC) as emulsifier.The suspension of montmorillonite was slowly dropped into the emulsion.Through the interaction between the negative charges on the montmorillonite layers and the cations on the surface of poly(styrene-acrylonitrile) particles, the montmorillonite layers and emulsion particles could assemble and absorb on each other by themselves.The change of δ voltage and particle size of the emulsion during the process of dropping was characterized, which demonstrated that the emulsion particles and montmorillonite layers absorbed on each other by the electrovalent bond and an intersectional structure was formed in the complex emulsion.Poly(styrene-acrylonitrile)/ montmorillonite nanocomposite was obtained after coagulation.The structure of nanocomposite was characterized with XRD and TEM.The results indicated that montmorillonite was exfoliated into layers with a thickness of several nanometers and uniformly dispersed in the polymer matrix.
基金Supported by the National Natural Science Foundation of China(No.51202160)
文摘Polystyrene （PS） @SiO2 core-shell microbeads with large pore and large particle size were prepared via layer-by-layer（LBL）assembly technique for potential applications in nano-micro composites. Negative silica nanoparticles synthesized via modified St6ber method and cationic poly （diallyldimethylammonium chloride） were alternately adsorbed on the surface of microbeads. Zeta potential, size, and morphology of the microbeads were monitored during LBL assembly process to ensure the successful deposition of silica nanoparticles. The porous shell was characterized using nitrogen adsorption and desorption analyses, and the surface area, volume and diame- ter of the pores were derived. It is found that the porous shell thickness and the pore size can be tuned by changing the coating times of silica nanoparticles. Finally, PS@SiO2 core-shell microbeads with 5 grn PS solid core and 350 nm mesoporous shell （mean BJH pore diameter is ~27 nm） were used to load CdSe/ZnS quantum dots （QDs）. The fluorescence microscopic image and the optical amplification of the QDs-embedded microbeads （QDBs） indicate that the as-prepared core-shell microbeads can provide adequate space for QDs and may be useful for further application of nano-micro composites.
