Microspheres coated with a perfectly conductive surface have many advantages in the applications of biosensors and micro-electromechanical systems. Polystyrene microspheres with the diameter of 10 μm were coated with...Microspheres coated with a perfectly conductive surface have many advantages in the applications of biosensors and micro-electromechanical systems. Polystyrene microspheres with the diameter of 10 μm were coated with a 50 nmthick gold layer using an electroless gold plating approach. Dielectrophoresis （DEP） for bare microspheres and shelled microspheres was theoretically analysed and the real part of the Clausius Mossotti factor was calculated for the two kinds of microspheres. The experiments on the dielectrophoretic characterisation of the uncoated polystyrene microspheres and gold coated polystyrene microspheres （GCPMs） were carried out. Experimental results showed that the gold coated polystyrene microspheres were only acted by a positive dielectrophoretic force when the frequency was below 40M Hz, while the uncoated polystyrene microspheres were governed by a negative dielectrophoretic force in this frequency range. The gold coated polystyrene microspheres were exploited to form the rnicrowire automatically according to their stable dielectrophoretic and electric characterisations.展开更多
Arrays of noble metal nanoparticles show potential applications in （bio-）sensing, optical storage, surface-enhanced spectroscopy, and waveguides. For all such potential devices, controlling the size, morphology, and...Arrays of noble metal nanoparticles show potential applications in （bio-）sensing, optical storage, surface-enhanced spectroscopy, and waveguides. For all such potential devices, controlling the size, morphology, and interparticle spacing of the nanoparticles is very important. Here, we combine seed-mediated growth with nanosphere lithography to study the controllable growth of gold nanoparticles （Au NPs）, in which the self-assembly monolayer of polystyrene （PS） on a silicon surface is used to guide the modification of allaunesilanes and the subsequent adsorption of gold seeds; seed-mediated growth is applied to controlling the morphology and size of Au NPs. The size of adsorption region （determining the number of adsorbed gold seeds） is controlled by etching PS microspheres with oxygen plasma or annealing PS microspheres at the glass transition temperature. The size and morphology of the Au NPs are controlled by changing growth conditions. In such a way, we have achieved the dual control of the obtained Au NPs. Preliminary results show that this strategy holds a great promise. This approach can also be extended to a wide range of materials and substrates.展开更多
The preparation methods of hollow polymer microspheres both at home and abroad are summarized, and their preparation mechanisms and developmental states are presented. These methods include the liquid droplet method, ...The preparation methods of hollow polymer microspheres both at home and abroad are summarized, and their preparation mechanisms and developmental states are presented. These methods include the liquid droplet method, dried-gel droplet method, self-assembly method, microencapsulation method, emulsion polymerization method and the template method. Hollow polystyrene microspheres are the most extensively studied in the research of hollow polymer microspheres. Through comparison of the advantages and disadvantages of different preparation methods, it is concluded that microencapsulation method is most suitable for preparing polystyrene hollow microspheres.展开更多
Macro-mesoporous γ-alumina support（MMA） was prepared by a sol-gel route in aqueous medium using pseudo-boehmite as aluminum source and polystyrene microspheres and Pluronic P123 as hard and soft dual templates,resp...Macro-mesoporous γ-alumina support（MMA） was prepared by a sol-gel route in aqueous medium using pseudo-boehmite as aluminum source and polystyrene microspheres and Pluronic P123 as hard and soft dual templates,respectively.MMA had a BET specific surface area of about 259 m2 g-1,total pore volume of about 1.61 cm3 g-1,macropore diameter of about 102 nm,and mesopore diameter of about 14 nm.Re2O7/MMA and conventional Re2O7/Al2O3 were prepared by a incipient-wetness impregnation method,and their catalytic performances in the metathesis of 1-butene and 2-butene were tested in a fixed-bed tubular reactor.The result showed that Re2O7/MMA possessed higher activity and far longer working life-span than conventional Re2O7/Al2O3.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 51075087)the State Key Laboratory of Fluid Power Transmission and Control,ZheJiang University of China (Grnat No. GZKF-201004)the China Scholarship Council(Grant No. 2009612129)
文摘Microspheres coated with a perfectly conductive surface have many advantages in the applications of biosensors and micro-electromechanical systems. Polystyrene microspheres with the diameter of 10 μm were coated with a 50 nmthick gold layer using an electroless gold plating approach. Dielectrophoresis （DEP） for bare microspheres and shelled microspheres was theoretically analysed and the real part of the Clausius Mossotti factor was calculated for the two kinds of microspheres. The experiments on the dielectrophoretic characterisation of the uncoated polystyrene microspheres and gold coated polystyrene microspheres （GCPMs） were carried out. Experimental results showed that the gold coated polystyrene microspheres were only acted by a positive dielectrophoretic force when the frequency was below 40M Hz, while the uncoated polystyrene microspheres were governed by a negative dielectrophoretic force in this frequency range. The gold coated polystyrene microspheres were exploited to form the rnicrowire automatically according to their stable dielectrophoretic and electric characterisations.
基金Project supported by the National Natural Science Foundation of China （Grant No 10334060） and The State Key Development Program for Basic Research of China （Grant No 2005CB623602）.
文摘Arrays of noble metal nanoparticles show potential applications in （bio-）sensing, optical storage, surface-enhanced spectroscopy, and waveguides. For all such potential devices, controlling the size, morphology, and interparticle spacing of the nanoparticles is very important. Here, we combine seed-mediated growth with nanosphere lithography to study the controllable growth of gold nanoparticles （Au NPs）, in which the self-assembly monolayer of polystyrene （PS） on a silicon surface is used to guide the modification of allaunesilanes and the subsequent adsorption of gold seeds; seed-mediated growth is applied to controlling the morphology and size of Au NPs. The size of adsorption region （determining the number of adsorbed gold seeds） is controlled by etching PS microspheres with oxygen plasma or annealing PS microspheres at the glass transition temperature. The size and morphology of the Au NPs are controlled by changing growth conditions. In such a way, we have achieved the dual control of the obtained Au NPs. Preliminary results show that this strategy holds a great promise. This approach can also be extended to a wide range of materials and substrates.
文摘The preparation methods of hollow polymer microspheres both at home and abroad are summarized, and their preparation mechanisms and developmental states are presented. These methods include the liquid droplet method, dried-gel droplet method, self-assembly method, microencapsulation method, emulsion polymerization method and the template method. Hollow polystyrene microspheres are the most extensively studied in the research of hollow polymer microspheres. Through comparison of the advantages and disadvantages of different preparation methods, it is concluded that microencapsulation method is most suitable for preparing polystyrene hollow microspheres.
基金supported by the National Natural Science Foundation of China (Grant No:20976192)SINOPEC Jiujiang Petrochemical Company (G2810-09-ZS-0027)
文摘Macro-mesoporous γ-alumina support（MMA） was prepared by a sol-gel route in aqueous medium using pseudo-boehmite as aluminum source and polystyrene microspheres and Pluronic P123 as hard and soft dual templates,respectively.MMA had a BET specific surface area of about 259 m2 g-1,total pore volume of about 1.61 cm3 g-1,macropore diameter of about 102 nm,and mesopore diameter of about 14 nm.Re2O7/MMA and conventional Re2O7/Al2O3 were prepared by a incipient-wetness impregnation method,and their catalytic performances in the metathesis of 1-butene and 2-butene were tested in a fixed-bed tubular reactor.The result showed that Re2O7/MMA possessed higher activity and far longer working life-span than conventional Re2O7/Al2O3.
