In the presence of p-toluene sulfonic acid (TSA) as a dopant, polyaniline (PAni) nanofibers, (about 80^-65 nm in diameter) were successfully synthesized with a chemical template-free method. It was found that the form...In the presence of p-toluene sulfonic acid (TSA) as a dopant, polyaniline (PAni) nanofibers, (about 80^-65 nm in diameter) were successfully synthesized with a chemical template-free method. It was found that the formation probability, morphology, and diameter of the resulting PAni-TSA nanofibers were sensitive to the synthetic conditions, such as reaction temperature, the molar ratio of TSA to aniline, and the concentration of TSA in the polymerization media. The molecular structure was characterized by using the FT-IR, Raman spectra and X-ray diffraction, which shows that the main chain structure of PAni-TSA nanofibers was in agreement with that of granular PAni.展开更多
Fluorescein/polyvinyl pyrrolidone （PVP） composite nanofibers with different fluorescein loadings （with a weight concentration of 0-5.0%） are fabricated via electrospinning. Morphologies, structures and photolumine...Fluorescein/polyvinyl pyrrolidone （PVP） composite nanofibers with different fluorescein loadings （with a weight concentration of 0-5.0%） are fabricated via electrospinning. Morphologies, structures and photoluminescent （PL） prop- erties of these straight, helical or wavelike fibers are characterized by scanning electron microscopy （SEM）, fluorescence microscopy and a spectrophotometer. It is found that the maximum emission of the as-spun fluorescein/PVP fibers occurs at 510 nm. The PL intensity of the composite fiber increases with fluorescein concentration, then fluorescence quenching appears when the concentration reaches 1.67%. The mechanism of fluorescence quenching of fiuorescein is discussed. In addition, the composite fibers exhibit a much stronger PL intensity than fluorescein/PVP bulk film owing to larger specific surface area, which makes them promising materials for biomedical applications such as probes and sensors.展开更多
High yield and quality mutli-walled carbon nanotube (MWNT) bundles and carbon nanofibers were synthesized by catalytic decomposition of methane over Co/MgMoO4 catalyst at 1 000 ℃. TEM studies showed that the products...High yield and quality mutli-walled carbon nanotube (MWNT) bundles and carbon nanofibers were synthesized by catalytic decomposition of methane over Co/MgMoO4 catalyst at 1 000 ℃. TEM studies showed that the products were mainly carbon nanofibers without carrier gas and were all MWNT bundles with hydrogen or nitrogen as carrier gas. Thermal gravimetric analyses (TGA) on the raw product indicated that the purity of MWNT was higher than 95wt%. The growth mechanism of carbon nanofibers and MWNTs was also discussed.展开更多
采用静电纺丝的方法研制了再生丝素纳米纤维（ERSF）膜，纤维直径为50～1000nm。将脱胶后的桑蚕丝溶解在摩尔比为1：2：8的60℃EaCl2／CH3CH2OH/H2O三元体系中，将该溶液冷冻干燥后溶解在98％的甲酸中得到再生丝素溶液，对其进行静电纺...采用静电纺丝的方法研制了再生丝素纳米纤维（ERSF）膜，纤维直径为50～1000nm。将脱胶后的桑蚕丝溶解在摩尔比为1：2：8的60℃EaCl2／CH3CH2OH/H2O三元体系中，将该溶液冷冻干燥后溶解在98％的甲酸中得到再生丝素溶液，对其进行静电纺丝。研究了不同纺丝条件下，静电纺再生丝素纤维的直径分布。研究发现：在一定的电压和喷丝头与接收屏的距离（C-D）下，7wt％是具有良好可纺性的临界浓度。纤维的直径随着溶液浓度的增加而增大，随着C-D的增加而减小，并且在C—D较大时可以获得较均匀的纤维。电压是另一个影响纤维直径的重要因素，当电压高于某一数值时，可以纺得细而均匀的纳米级再生丝素纤维。在9wt％，12cm C-D and 15KV的纺丝条件下，80％的纤维直径在50～150nm之间。由于所纺得的再生丝素纤维膜在水中会产生收缩，因此用甲醇和丙酮对其进行处理。力学性能是影响纤维膜实际使用的重要性能，我们测定和分析了静电纺再生丝素纤维膜处理前后的力学性能。展开更多
文摘In the presence of p-toluene sulfonic acid (TSA) as a dopant, polyaniline (PAni) nanofibers, (about 80^-65 nm in diameter) were successfully synthesized with a chemical template-free method. It was found that the formation probability, morphology, and diameter of the resulting PAni-TSA nanofibers were sensitive to the synthetic conditions, such as reaction temperature, the molar ratio of TSA to aniline, and the concentration of TSA in the polymerization media. The molecular structure was characterized by using the FT-IR, Raman spectra and X-ray diffraction, which shows that the main chain structure of PAni-TSA nanofibers was in agreement with that of granular PAni.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11074138,11004114,60906054, and50825206)the Shandong Provincial Natural Science Foundation for Distinguished Young Scholars,China (Grant No. JQ201103)+2 种基金the Taishan Scholars Program of Shandong Province, Chinathe National Basic Research Program of China (Grant No. 2012CB722705)the National High Technology Research and Development Program of China (Grant No. 2011AA100706)
文摘Fluorescein/polyvinyl pyrrolidone （PVP） composite nanofibers with different fluorescein loadings （with a weight concentration of 0-5.0%） are fabricated via electrospinning. Morphologies, structures and photoluminescent （PL） prop- erties of these straight, helical or wavelike fibers are characterized by scanning electron microscopy （SEM）, fluorescence microscopy and a spectrophotometer. It is found that the maximum emission of the as-spun fluorescein/PVP fibers occurs at 510 nm. The PL intensity of the composite fiber increases with fluorescein concentration, then fluorescence quenching appears when the concentration reaches 1.67%. The mechanism of fluorescence quenching of fiuorescein is discussed. In addition, the composite fibers exhibit a much stronger PL intensity than fluorescein/PVP bulk film owing to larger specific surface area, which makes them promising materials for biomedical applications such as probes and sensors.
文摘High yield and quality mutli-walled carbon nanotube (MWNT) bundles and carbon nanofibers were synthesized by catalytic decomposition of methane over Co/MgMoO4 catalyst at 1 000 ℃. TEM studies showed that the products were mainly carbon nanofibers without carrier gas and were all MWNT bundles with hydrogen or nitrogen as carrier gas. Thermal gravimetric analyses (TGA) on the raw product indicated that the purity of MWNT was higher than 95wt%. The growth mechanism of carbon nanofibers and MWNTs was also discussed.
基金The work was financially supported by science andtechnology office of Jiangsu province(BE2004368)
文摘采用静电纺丝的方法研制了再生丝素纳米纤维（ERSF）膜，纤维直径为50～1000nm。将脱胶后的桑蚕丝溶解在摩尔比为1：2：8的60℃EaCl2／CH3CH2OH/H2O三元体系中，将该溶液冷冻干燥后溶解在98％的甲酸中得到再生丝素溶液，对其进行静电纺丝。研究了不同纺丝条件下，静电纺再生丝素纤维的直径分布。研究发现：在一定的电压和喷丝头与接收屏的距离（C-D）下，7wt％是具有良好可纺性的临界浓度。纤维的直径随着溶液浓度的增加而增大，随着C-D的增加而减小，并且在C—D较大时可以获得较均匀的纤维。电压是另一个影响纤维直径的重要因素，当电压高于某一数值时，可以纺得细而均匀的纳米级再生丝素纤维。在9wt％，12cm C-D and 15KV的纺丝条件下，80％的纤维直径在50～150nm之间。由于所纺得的再生丝素纤维膜在水中会产生收缩，因此用甲醇和丙酮对其进行处理。力学性能是影响纤维膜实际使用的重要性能，我们测定和分析了静电纺再生丝素纤维膜处理前后的力学性能。
