Silicon dioxide sol was synthesized by silicon in the presence of alkali catalyst. SiO_2 nanoparticles (size in 8-15 nm) aqueous dispersion was prepared by using dispersion and surface modification in situ. The effect...Silicon dioxide sol was synthesized by silicon in the presence of alkali catalyst. SiO_2 nanoparticles (size in 8-15 nm) aqueous dispersion was prepared by using dispersion and surface modification in situ. The effects of reaction time, temperature, medium pH value, dispersant and surface-modifier on their diameters, sizes distribution and dispersion stability were also studied.The experimental results show that the preparation method can effectively resolve the dispersion stability of SiO_2 nanoparticles in water.展开更多
A series of CdS nanoparticles with different surfaces were prepared by colloidal chemical method and reverse micelle method. Their second-order nonlinear optical (NLO) properties were experimentally studied in solutio...A series of CdS nanoparticles with different surfaces were prepared by colloidal chemical method and reverse micelle method. Their second-order nonlinear optical (NLO) properties were experimentally studied in solution by newly developed hyper-Rayleigh scattering (HRS) technique. The results show that 'per particle' first-order hyperpolarizability beta values are sensitive To the synthetic method and the surface chemical modification.展开更多
Atom transfer radical polymerization (ATRP) using cuprous chloride/2,2'-bipyridine (bipy) was applied to graft polymerization of styrene on the surface of silica nanoparticles to synthesize polymer-inorganic hybri...Atom transfer radical polymerization (ATRP) using cuprous chloride/2,2'-bipyridine (bipy) was applied to graft polymerization of styrene on the surface of silica nanoparticles to synthesize polymer-inorganic hybrid nanoparticles, 2-(4Chloromethylphenyl) ethyltriethoxysilane (CTES) was immobilized on the surface of silica nanoparticles through condensation reaction of the silanol groups on silica with triethoxysilane group of CTES. Then ATRP of St was initiated by this surface-modified silica nanoparticles bearing benzyl chloride groups, and formed PSt graft chains on the surface of silica nanoparticles. The thickness of the graft chains increased with reaction time. End group analysis confirmed the occurrence of ATRP. Thermal analysis indicated that thermal stabilization of these resulting hybrid nanoparticles also increases with polymerization conversion. The results above show that this 'grafting from' reaction could be used for the preparation of polymer-inorganic hybrid nanoparticles with controlled structure of the polymer's end groups.展开更多
Titanic acid nanotubes (H2Ti2O4(OH)2) were surface-modified with cetyl alcohol through dehydration reaction because of existence of Ti–OH. The modified nanotubes were characterized by transmission electron microscopy...Titanic acid nanotubes (H2Ti2O4(OH)2) were surface-modified with cetyl alcohol through dehydration reaction because of existence of Ti–OH. The modified nanotubes were characterized by transmission electron microscopy (TEM), Fourier Transform Infrared (FT-IR) spectrometry and pho-toluminescence (PL) spectra. The results indicate that the modified nanotubes can be easily dis-persed into organic solvent such as chloroform and toluene in contrast with the unmodified nanotubes, which makes it easier to be assembled by LB technique. Moreover, the Ti-O-CH2(CH2)14CH3 on the surface of the nanotubes can hinder the adsorption of water and consequently the photoluminescence property of the nanotubes can be stabilized. Even though kept in humid condition or in air for a long time, the modified nanotubes also maintain the special photoluminescence property in the visible re-gion.展开更多
文摘Silicon dioxide sol was synthesized by silicon in the presence of alkali catalyst. SiO_2 nanoparticles (size in 8-15 nm) aqueous dispersion was prepared by using dispersion and surface modification in situ. The effects of reaction time, temperature, medium pH value, dispersant and surface-modifier on their diameters, sizes distribution and dispersion stability were also studied.The experimental results show that the preparation method can effectively resolve the dispersion stability of SiO_2 nanoparticles in water.
基金National Natural Science Foundation of China! (No.59582005)
文摘A series of CdS nanoparticles with different surfaces were prepared by colloidal chemical method and reverse micelle method. Their second-order nonlinear optical (NLO) properties were experimentally studied in solution by newly developed hyper-Rayleigh scattering (HRS) technique. The results show that 'per particle' first-order hyperpolarizability beta values are sensitive To the synthetic method and the surface chemical modification.
基金This project was supported by the National Natural Science Foundation of China to K.Y Qiu (Grant No. 29874002) and Outstanding Young Scientist Award to Y. Wei (Grant No. 29825504)
文摘Atom transfer radical polymerization (ATRP) using cuprous chloride/2,2'-bipyridine (bipy) was applied to graft polymerization of styrene on the surface of silica nanoparticles to synthesize polymer-inorganic hybrid nanoparticles, 2-(4Chloromethylphenyl) ethyltriethoxysilane (CTES) was immobilized on the surface of silica nanoparticles through condensation reaction of the silanol groups on silica with triethoxysilane group of CTES. Then ATRP of St was initiated by this surface-modified silica nanoparticles bearing benzyl chloride groups, and formed PSt graft chains on the surface of silica nanoparticles. The thickness of the graft chains increased with reaction time. End group analysis confirmed the occurrence of ATRP. Thermal analysis indicated that thermal stabilization of these resulting hybrid nanoparticles also increases with polymerization conversion. The results above show that this 'grafting from' reaction could be used for the preparation of polymer-inorganic hybrid nanoparticles with controlled structure of the polymer's end groups.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 90306010 and 20371015) State Key Basic Research '973' Plan of China (Grant No. 2002CCC02700).
文摘Titanic acid nanotubes (H2Ti2O4(OH)2) were surface-modified with cetyl alcohol through dehydration reaction because of existence of Ti–OH. The modified nanotubes were characterized by transmission electron microscopy (TEM), Fourier Transform Infrared (FT-IR) spectrometry and pho-toluminescence (PL) spectra. The results indicate that the modified nanotubes can be easily dis-persed into organic solvent such as chloroform and toluene in contrast with the unmodified nanotubes, which makes it easier to be assembled by LB technique. Moreover, the Ti-O-CH2(CH2)14CH3 on the surface of the nanotubes can hinder the adsorption of water and consequently the photoluminescence property of the nanotubes can be stabilized. Even though kept in humid condition or in air for a long time, the modified nanotubes also maintain the special photoluminescence property in the visible re-gion.
