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201.
A novel organic/inorganic hybrid honeycomb patterned porous thin film was prepared using the breath‐figure method combined with a sol‐gel process. An in situ formed gelable block copolymer, formed by mixing poly(styrene‐alt‐maleic anhydride)‐block‐polystyrene (P(St‐a‐MAn)‐b‐PS) and 3‐aminopropyltrimethoxysilane (APS), was used as the structure directing agent. The porous film produced was dipped into an acid aqueous solution to induce a sol‐gel process in the wall of film. As a result of gelation, the structure of this film transformed into a crosslinked silica oxide hybridized with PS, and this film resisted those organic solvents which were once good solvents for the copolymer precursor.
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Eu(TTA)_3/MCM-41介孔复合体的溶胶凝胶法组装 总被引:2,自引:1,他引:1
利用溶胶 凝胶法将稀土配合物Eu(TTA) 3 组装到MCM 41介孔分子筛的孔道中 ,并初步认定客体分子Eu(TTA) 3 是以加合物形式包裹于表面活性剂胶束中。该法制得的介孔复合体Eu(TTA) 3/MCM 41,用XRD、HRTEM技术证实具有短程有序的、规整的六方介孔结构和大小分布均匀的纳米晶粒。对其光致发光和荧光寿命的研究发现 :与乙醇溶液中相比 ,Eu3 的荧光寿命没有发生改变 ,但Stokes位移却明显增大 ;复合体中 ,能量是从主体MCM 41传递到客体Eu(TTA) 3 上。 相似文献
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Dong Liang 《辐射效应与固体损伤》2013,168(7-8):596-605
ABSTRACTA nano-Mn3B7O13Cl crystal was synthesized by a sol–gel method, and the structure, morphology and size were characterized by X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy. Effects of gamma radiation on the microstructure, luminescence properties, and medical performance for Mn3B7O13Cl have been discussed. The results show that Mn3B7O13Cl nanocrystals are uniform, and the average crystal size is about 50?nm. Under the 202?Gy measurement of gamma-ray irradiation, there are a large number of crystal defects in a chambersite crystal, and the defect is given priority with point defects and dislocations especially in gamma-ray irradiation with high energy. The luminescence intensity of natural chambersite in red light wavelengths increased obviously, and the luminescence intensity increased by 3.5 times. Nano-Mn3B7O13Cl exhibited the most significant antitumor activity and antiseptic effects. The best inhibition concentration of natural chambersite to A549 is 100?µg/ml, and its inhibition rate reaches 80%. Addition of natural chambersite in the solution significantly lowers the concentrations of Escherichia coli BL21, and the value is reduced by 97.6%. Therefore, chambersite has important application in the field of medical and shielding materials. 相似文献
206.
Mark A. Ward Theoni K. Georgiou 《Journal of polymer science. Part A, Polymer chemistry》2013,51(13):2850-2859
The aim of this study was to investigate the effect of the asymmetry of the triblock copolymers on their thermoresponsive self‐assembly behavior. To this end, nine ABA‐type triblock copolymers with n‐butyl methacrylate and 2‐(dimethylamino)ethyl methacrylate (DMAEMA) consisting of the A and the B blocks, respectively, were synthesized. Polymers of three different DMAEMA contents (50, 60, and 70 wt %) were synthesized while varying the length ratio of the two hydrophobic A blocks. Specifically, one symmetric ABA triblock copolymer and two asymmetric ABA′ triblock copolymers with the length of the second A block to be twice or four times bigger than the length of the first A block (AB2A and AB4A triblock copolymer) were synthesized for each DMAEMA composition. Three statistical copolymers were also synthesized for comparison. The thermoresponsive behavior of the copolymers was studied and it was found that the cloud point and rheological properties of the polymers were strongly affected by the architecture (statistical vs. block) and less strongly by the DMAEMA composition and the asymmetry of the polymers. Nevertheless, interestingly the asymmetry of the ABA triblock copolymers did influence the thermoresponsive behavior with the more symmetric polymers presenting a sol–gel transition at lower temperatures. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2850–2859. 相似文献
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Jie Dong Chaoqing Yin Yumei Zhang Qinghua Zhang 《Journal of Polymer Science.Polymer Physics》2014,52(6):450-459
Copolyimides were synthesized in N‐methyl‐2‐pyrrolidone (NMP) to prepare polyimide (PI) solutions with various concentrations, and gels can form in PI/NMP solution with a suitable concentration or at a low temperature. Gel–sol transition in the PI/NMP solution has been investigated through a combination of polarized optical microscope, differential scanning calorimeter measurement, and rheological measurements. According to Winter–Chambon theory, the critical gel point is 12 wt %, and the loss tangent (tan δ) shows frequency independence. Gel–sol transition temperature (Tgel) for the 13 wt % solution is around 65 °C. Below the Tgel, the gel exhibits strong optical planar texture, indicating the formation of a fully anisotropic phase, which has a great importance for the fabrication of PI fibers by gel‐spinning. Dynamic temperature sweep measurements show that the formation of the gel from solution is thermoreversible and is significantly delayed in the cooling process. Under the favorable conditions, the tensile strength and modulus of the fibers derived from the solution are about 0.7 and 12.5 GPa using gel‐spinning method, which is believed to afford broad application potential in preparing high‐performance PI fibers. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 450–459 相似文献
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