共查询到20条相似文献,搜索用时 140 毫秒
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报道了一种应用光化学法一步原位合成具有良好亲水性和生物相容性的PEGMA磁性纳米凝胶的方法.在亲水性Fe3O4纳米粒子水体系中,以甲基丙烯酸聚乙二醇酯(PEGMA)N单体,N,N-亚甲基双丙烯酰胺(MBA)为交联剂,紫外光辐照下原位聚合制备了聚(甲基丙烯酸聚乙二醇酯)磁性纳米凝胶(简称为PEGMA磁性纳米凝胶),应用傅立叶变换红外光谱(FTIR)和热重分析仪(TGA)对磁性纳米凝胶的表面官能团和组分进行了分析,结果显示经紫外辐照后PEGMA成功包覆在Fe3O4纳米粒子表面,从而制备得到PEGMA磁性纳米凝胶,磁性Fe3O4含量高达53.4%;对磁性纳米凝胶的形貌、粒径、表面Zeta电位及磁学性质等进行了表征,结果显示磁性纳米凝胶形状较规则,具有核-壳结构,干燥状态下平均粒径约为46nm,而湿态下平均水合粒径为68.4nm,表明其外层的水凝胶在水相中具有较强的吸水膨胀能力;磁性纳米凝胶具有超顺磁性,饱和磁化强度为58.6emu/g,在生理pH下,磁性纳米凝胶的表面Zeta电位为-16.3~-17.3mV,能够减少与血红蛋白的吸附作用,可在血液中保持稳定.在其载药性能中发现,PEGMA磁性纳米凝胶对模型药物阿霉素具有良好缓释性能.该超顺磁性纳米凝胶具有高的饱和磁化强度,生理pH下负的表面Zeta电位,以及良好的亲水性和生物相容性等特性,预示着在靶向载药等生物医学领域有着广泛的应用前景. 相似文献
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在室温条件下, 采用超声辅助电化学方法合成了几种三维铂纳米电催化剂. 利用透射电子显微镜(TEM)、X射线粉末衍射(XRD)以及电化学测试对该三维铂纳米电催化剂进行了表征. 结果表明, 这些铂纳米电催化剂的形貌、结构可以通过添加不同的形貌控制剂来调控, 在水溶液、聚乙烯吡咯烷酮(PVP)溶液和十六烷基三甲基氯化铵(CTAC)溶液中分别得到了立方海绵状铂、分枝状铂和球形多孔状铂. 其中, 球形多孔状铂纳米电催化剂由于其多孔的结构, 因此具有更高的电化学活性面积, 对氧气还原和甲醇氧化反应具有更好的催化作用. 相似文献
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聚酰亚胺/二氧化硅纳米尺度复合材料的研究 总被引:72,自引:0,他引:72
通过正硅酸乙酯(TEOS)在聚酰胺酸(PAA)的N,N’ 二甲基乙酰胺(DMAc),溶液中进行溶胶 凝胶反应,制备出不同二氧化硅含量的聚酰亚胺/二氧化硅(PI/SiO2)复合薄膜材料.二氧化硅含量低于10wt%的样品是透明浅黄色薄膜;二氧化硅含量高于10wt%的样品是不透明棕黄色薄膜.利用红外光谱、扫描电镜、热失重分析、动态力学分析、热膨胀系数测试和应力 应变测试等方法研究了此类材料的结构与性能.结果表明,PI/SiO2纳米复合材料具有较聚酰亚胺更高的热稳定性和更高的模量;线膨胀系数显著降低;拉伸强度和断裂伸长随二氧化硅含量而变化,分别在10wt%和30wt%附近出现最大值 相似文献
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Sb2O3/TiO2纳米复合物的合成及性质研究 总被引:1,自引:1,他引:0
以改进的溶胶-凝胶法制备了Sb2O3/TiO2纳米复合物,用扫描电镜、X射线粉末衍射、傅立叶红外光谱、紫外-可见光谱以及荧光等测试技术对产物进行了分析和表征.结果表明:所得纳米复合物颗粒分散均匀,具有锐钛矿相结构,平均粒径约为10nm.还研究了所得产物的光催化性质、电化学性质及电化学发光行为.结果表明:Sb2O3的掺入可以提高TiO2的光催化效果,当反应物中m(Sb2O3)/m(TiO2)=10%时,所得纳米复合物对亚甲基蓝和罗丹明B的光催化效果最好. 相似文献
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通过溶胶-凝胶法以十八烷基三甲基溴化铵(STAB)自组装体为模板和非离子型联二萘酚衍生物(S)作为手性添加剂制备螺旋介孔二氧化硅。样品利用扫描电镜、透射电镜、X-光衍射以及氮气吸附-脱附进行了表征。结果表明:反应混合物中S与STAB的物质的量之比对介孔二氧化硅的形貌及孔结构有很大影响。改变nS∶nSTAB比,从0.1∶1到0.4∶1时,其结构从螺旋纳米棒状变为表面具有环形层状孔的纳米棒,孔道由沿着纳米棒长轴方向转变为同心环状。当nS∶nSTAB=0.5∶1时,得到类似皱缩花瓣的纳米颗粒。该手性添加剂的引入并没有改变左右手螺旋纳米棒的比例。 相似文献
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Xue P Lu R Li D Jin M Tan C Bao C Wang Z Zhao Y 《Langmuir : the ACS journal of surfaces and colloids》2004,20(25):11234-11239
A new cholesterol organogelator 1 was synthesized, which was confirmed as an effective gelator for various organic solvents and could self-assemble into network fibers in some organic solvents. Moreover, gelator 1 could act as templates for the synthesis of various CuS nanofibers with different helical pitches. For example, when H(2)S was used as the sulfur source, straight and bending helical CuS nanofibers with a pitch of 100-200 nm could be fabricated in butyl acetate and benzene-butanol gel systems, respectively, while bending CuS nanofibers with a similar helical pitch (ca. 50 nm) could be obtained when thioacetamide was used as the sulfur source in both gel systems. It was first found that the morphologies of inorganic nanofibers could be controlled by the binding sites between the inorganic precursor and the organogel. 相似文献
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Yang Y Suzuki M Shirai H Kurose A Hanabusa K 《Chemical communications (Cambridge, England)》2005,(15):2032-2034
Aligned nanofibers with inner-helical mesoporous silica were synthesized using chiral gelator as template under basic conditions and a shear flow. 相似文献
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One-step fabrication of silver nanoparticle embedded polymer nanofibers by radical-mediated dispersion polymerization 总被引:2,自引:0,他引:2
Silver nanoparticle embedded poly(vinyl alcohol)-poly(methyl methacrylate) nanofibers, ca. 30 nm in diameter and ca. 60 microm in length, were fabricated by one-step radical-mediated dispersion polymerization using 2,2'-azobis(isobutyronitrile) to reduce the silver ions. In this methodology, PVA acted both as a gelator to form the nanofibers and as a stabilizer to protect the silver clusters from sintering. 相似文献
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A Library of Multipurpose Supramolecular Supergelators: Fabrication of Structured Silica,Porous Plastics,and Fluorescent Gels
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Supramolecular gels find applications in various fields. Usually, a specific gelator is useful only for a specific application. This one‐gelator‐one‐application format is one factor that limits the usefulness of supramolecular gels. We report the synthesis of a library of gelators from a common core by using a click‐chemistry approach. Thus, the click reaction of β‐azido‐4,6‐O‐benzylidene–galactopyranoside ( 1 ) with various alkynes gave 11 different gelators having varying gelation abilities. Whereas gelators having alkyl‐chain substituents congealed alkanes and tetraethylorthosilicate (TEOS), the gelators having aromatic substituents congealed aromatic solvents. We exploited this difference in gelling behavior in the templated synthesis of silica rods and porous plastics. The styrene gel of gelator 2 j was polymerized, and the gelator was removed by washing to obtain porous polystyrene. The TEOS gel of gelator 2 b was polymerized to silica, and the gelator template was removed by calcination to give microstructured silica rods. We also developed fluorescent gelator 2 f by this method, which might find applications by virtue of its fluorescence in the assembled state. 相似文献
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Mazurenko I Etienne M Ostermann R Smarsly BM Tananaiko O Zaitsev V Walcarius A 《Langmuir : the ACS journal of surfaces and colloids》2011,27(11):7140-7147
The modification of platinum nanofibers by silica using the electrochemically-assisted deposition is reported here. Pt nanofibers are obtained by electrospinning and deposited on a glass substrate. The electrochemically-assisted deposition of the sol-gel material then gives the unique possibility to finely tune the silica film thickness around these nanofibers. It also allows the successful encapsulation of a biomolecule (glucose oxidase was chosen here as a model) while retaining its biological activity, as pointed out via the electrochemical monitoring of H(2)O(2) produced upon addition of glucose in the medium. This silica-glucose oxidase composite offers the possibility of comparing systematically the influence of the deposition time on the bioelectrode response and to compare it with the particular features of the deposits. It was found that the film first grew uniformly around the nanofibers and then started to deposit between them, covering the whole sample (fibers and glass substrate), and tended to fully embed the nanofibers for prolonged deposition. The thickness of the silica film is critical for the electroactivity of the biocomposite, the best response being obtained for a silica layer thickness in the range of the fiber diameter (~50 nm). 相似文献
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Synthesis of rod-like mesoporous silica with hexagonal appearance using sodium silicate as precursor 总被引:1,自引:0,他引:1
Using sodium silicate as precursor, rod-like mesoporous silica with hexagonal appearance was synthesized by controlling the pH value of a mixed micelles solution of cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammonium chloride (CTAC) during hydrolysis of ethyl acetate. The resulting mesoporous silica was characterized by small angle X-ray diffraction, nitrogen gas adsorption-desorption measurement and scanning electron microscopy. Results showed that the regular rod-like shapes with hexagonal appearance were obtained at a 9:1 molar ratio of CTAB to CTAC, and that the amounts and lengths of the rod-like mesoporous silica particles decreased with decreasing CTAB to CTAC molar ratio. There existed a type IV adsorption isotherm and an H1 hysteresis loop in N2 gas adsorption-desorption curves. 相似文献
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静电纺丝法制备硫酸化的二氧化锆/二氧化硅复合纤维 总被引:1,自引:0,他引:1
将电纺丝技术与溶胶-凝胶技术相结合, 制备了SZ粒子分布于SiO2纤维外壁的硫酸化的二氧化锆/二氧化硅复合纤维. 与常见的SZ复合催化剂相比, 采用SiO2纤维负载SZ不仅可以解决粉体材料带来的难以与反应体系分离等弊病, 同时功能粒子SZ分布与纤维外壁的结构也提高了功能粒子的利用率. 相似文献
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Well-ordered mesostructured/mesoporous silica nanofibers have been synthesized in a quiescent dilute aqueous cationic surfactant/silica precursor reaction mixture under strong acidic conditions. These nanofibers have diameters ranging from 50 to 300 nm and lengths up to millimeters. Transmission electron microscopy (TEM) studies show that the nanofibers exhibit either a circular architecture with the pore channels running in a circular direction around the fiber axis or a longitudinal architecture with the pore channels running parallel to the fiber axis. The pore channels in both arrangements are hexagonally packed. The circular or longitudinal architecture can be selectively obtained during synthesis by varying reaction temperature or using inorganic salts as additives. 相似文献
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Tae Kyu Kim Euh Duck Jeong Chae Young Oh Myung Ho Hyun Mee Sung Lee Hae Kyeong Moon Jong-Pil Kim Ok-Sang Jung F. Nawaz Khan Jong Sung Jin 《Chemical Papers》2011,65(4):495-503
The 1,2-diphenylethylenediamine-based neutral or cationic organogelator-templates, currently employed in the production of
silica nanomaterials, were initially evaluated for their versatile gelation ability and found to be gelled in the majority
of organic solvents tested. Scanning electron microscope and transmission electron microscope, images of neutral organogels
made from different solvents revealed that they assembled into a plate-shaped, or rod-shaped morphology, respectively in ethanol
or butan-1-ol and in acetonitrile or tetrahydrofurane. Similarly, a 1: 1 mixture (mass) of neutral and cationic gelators formed
different morphologies in the solvents tested. Sol-gel polycondensation of tetraethoxy silane using either individual gels
(neutral or cation) or a 1: 1 mixture of gels was explored. The experimental results and the scanning electron microscopy
and transmission electron microscopy images revealed that silica nanotubes with an inner diameter of 82 nm and an outer diameter
of 620 nm were obtained from the 1: 1 mixture of neutral and cationic gelator in ethanol, whereas silica nanoparticles were
obtained using gels made in the other solvents tested. 相似文献
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Hybrid silica-PVA nanofibers via sol-gel electrospinning 总被引:1,自引:0,他引:1
Pirzada T Arvidson SA Saquing CD Shah SS Khan SA 《Langmuir : the ACS journal of surfaces and colloids》2012,28(13):5834-5844
We report on the synthesis of poly(vinyl alcohol) (PVA)-silica hybrid nanofibers via sol-gel electrospinning. Silica is synthesized through acid catalysis of a silica precursor (tetraethyl orthosilicate (TEOS) in ethanol-water), and fibers are obtained by electrospinning a mixture of the silica precursor solution and aqueous PVA. A systematic investigation on how the amount of TEOS, the silica-PVA ratio, the aging time of the silica precursor mixture, and the solution rheology influence the fiber morphology is undertaken and reveals a composition window in which defect-free hybrid nanofibers with diameters as small as 150 nm are obtained. When soaked overnight in water, the hybrid fibers remain intact, essentially maintaining their morphology, even though PVA is soluble in water. We believe that mixing of the silica precursor and PVA in solution initiates the participation of the silica precursor in cross-linking of PVA so that its -OH group becomes unavailable for hydrogen bonding with water. FTIR analysis of the hybrids confirms the disappearance of the -OH peak typically shown by PVA, while formation of a bond between PVA and silica is indicated by the Si-O-C peak in the spectra of all the hybrids. The ability to form cross-linked nanofibers of PVA using thermally stable and relatively inert silica could broaden the scope of use of these materials in various technologies. 相似文献