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1.
半导体纳米微粒在聚合物基体中的复合与组装   总被引:29,自引:4,他引:25  
总结了有关半导体纳米微粒在聚合物基体中的制备,复合与组装及性能研究等工作,对半导体纳米微粒的尺寸大小,粒度分布,表面修饰,复合过程及组装维数等控制问题进行了讨论。  相似文献   

2.
银纳米粒子的一步合成与表征   总被引:1,自引:1,他引:0  
在水和乙醇溶液中,以对巯基苯胺作为还原剂,利用一步法合成了银纳米微粒,并利用拉曼光谱仪考察了对巯基苯胺在银纳米微粒表面的自组装行为.结果表明,合成的银纳米微粒的形貌与介质的pH值密切相关;对巯基苯胺可在银纳米微粒表面自组装.  相似文献   

3.
壳聚糖基载药纳米微粒制备研究进展   总被引:17,自引:3,他引:14  
有关可生物降解多糖类纳米微粒用作给药载体的研究,近年颇受重视。简要评述了壳聚糖基载药纳米微粒的制备方法,包括共价交联、离子诱导、沉淀析出、大分子复合和自组装方法及其研究进展。  相似文献   

4.
CdS半导体纳米微粒的复合与组装   总被引:9,自引:0,他引:9  
总结了CdS半导体纳米微粒的复合与组装,并介绍了其应用方面的研究。  相似文献   

5.
纳米Sb2O3及其在云母表面的组装与阻燃性能   总被引:3,自引:0,他引:3  
纳米Sb2O3及其在云母表面的组装与阻燃性能;Sb2O3; 纳米微粒; 云母; 阻燃; 氯化石蜡  相似文献   

6.
聚合物Janus微粒是指具有各向异性微观结构的微/纳米聚合物粒子。因在乳液稳定、聚合物混合、可控组装、生物医药、多相催化和功能涂层等领域有重要的应用价值,聚合物Janus微粒材料的可控制备和应用研究已成为新型多功能和智能高分子材料研究的前沿领域。本文首先归纳了聚合物Janus微粒在制备方法、环境响应类型和应用领域的最新进展,进而分析了不同制备方法的优缺点。表面选择性修饰、微流体合成技术、自组装和种子聚合等方法都可用于制备具有可控尺寸、微观结构和表面性质的聚合物Janus微粒,但纳米级微粒微观结构的精确控制和大量合成还存在一定的挑战。环境响应性多组分聚合物Janus微粒在自组装和药物控释方面有其特殊的优势,而简单高效的种子聚合法有望应用于工业生产聚合物Janus固体表面活性剂。预计天然和多功能型聚合物Janus微粒的制备和应用研究将会是未来发展的趋势。  相似文献   

7.
正控制生物分子组装成具有特定形貌和功能的纳米组装体是当今材料化学和超分子化学的研究热点~1。目前,科学家通过分子自组装构筑了大量形貌各异的超分子组装体,并对其性能进行了探究;其研究重点主要集中在控制组装体的组装和解组装。如何有效的控制分子组装成特定的组装体面临着重大挑战,但对拓宽超分子材料的应用具有重要的促进意义~2。最近,南开大学元素有机国家重点实验室刘育教授课题组构筑了能够可逆转换的一维纳米管  相似文献   

8.
CdS纳米微粒在LB膜层隙聚集形态的AFM观察   总被引:2,自引:0,他引:2  
用LB技术制备纳米微粒与超薄有机膜的复合膜是近年来值得注意的研究进展*.利用该方法所制备出的材料既具有纳米粒子所特有的量子尺度效应,又具有LB股的分子层次有序、股厚可控以及易于组装等特点.它可用来制备结构可控的有机无机交替膜.而且,通过改变LB膜成膜材料和制备条件还可改变纳米粒子的光电特性.因此它在微电子学、光电子学、非线性光学及传感器等研究领域有着十分广阔的应用前景问.纳米微粒的聚集形态及LB膜在生成纳米微粒后的结构变化对材料的特性有着很大的影响.但采用一般的电镜技术或光谱分析手段均不能在实空间和…  相似文献   

9.
基于AFM纳米氧化技术的金纳米粒子定点组装   总被引:4,自引:0,他引:4  
二维纳米粒子矩阵列在纳米电子器件^[1,2]、表面增强喇曼活性基底^[3,4]、刻蚀掩模^[5]等领域具有广泛的应用前景。在这些纳米粒子阵列为内部,纳米粒子的排布是随机、无序的。这一缺点已经妨碍了纳米粒子阵列在上述领域中的进一步应用。基于此,人们开始关注纳米粒子的可控组装。传统的光刻技术^[6]、微接触印刷技术^[7]以及生物分子模板技术^[8]都被用来实现纳米粒子在固体表面上的可控组装,本实验室在纳米粒子的合成及可控组装方面也进行了研究^[7,9,11]。本文力图精确控制单个纳米粒子在基底表面上的组装位置。利用AFM纳米氧化技术。在硅表面构建了纳米级的化学图形化表面,通过不同的化学官能团,如甲基、氨基对金纳米粒子亲和性质的差异,实现了纳米粒子在固体表面的定点组装。  相似文献   

10.
《有机化学》2008,28(10)
用大环分子受体与聚合物,特别是导电型聚合物构筑而成的纳米超分子组装体在功能上所表现出来的独特性质吸引了越来越多的研究者的关注.早期研究所用的大环分子受体主要集中于冠醚和环糊精.近年来,新一代大环分子受体——葫芦脲逐渐成为研究热点.南开大学元素有机化学国家重点实验室刘育研究组首次报道了由葫芦脲和苯胺聚合物组成的超分子组装体,  相似文献   

11.
一种Q态纳米CdS的新型制备法——聚合物分散法   总被引:6,自引:0,他引:6  
闫云辉  章伟光  范军  纪欣 《化学学报》2005,63(14):1303-1306
采用一种Q态CdS的新型制备法——聚合物分散法, 即用水溶性聚合物溶液作为分散剂, 用2-巯基乙醇(或十二硫醇)作表面修饰剂, 在聚合物网络中构筑出四种粒径的、单分散性的Q-CdS. 通过UV-Vis光谱和TEM考察了Q-CdS的粒径及分布情况, 并用FL光谱研究了不同尺寸的Q-CdS的荧光性能. 结果表明, 采用聚合物分散法可以方便、快捷地得到粒径小且分布窄的Q-CdS纳米粒子, 这些粒子在紫外光谱及荧光光谱上均表现出明显的量子尺寸效应.  相似文献   

12.
Cadmium sulfide (CdS) quantum dots (QDs) encapsulated in block copolymer spheres were synthesized by an aqueous emulsion polymerization process. First, stable dispersions of CdS QDs in water were prepared using a polymer dispersant, either poly(acrylic acid) or a random copolymer having an average of ten acrylic acid and five butyl acrylate units. These polymer dispersants were prepared by reversible addition-fragmentation chain transfer polymerization. Then, the CdS QDs dispersed in water were encapsulated in a polystyrene shell using an emulsion polymerization process. Spectroscopic and microscopic techniques were used to characterize the resulting nanocomposites. Optical properties of QDs in polymer microspheres were investigated by UV-vis and fluorescence spectroscopic studies. Particle sizes of all CdS QD samples were calculated from absorption edges using Henglein's empirical curve. Transmission electron microscopy was used to determine the size and morphology of CdS QD samples. These observations were used to elucidate the mechanism of formation of the resulting well-defined polymer-encapsulated CdS nanoparticles.  相似文献   

13.
In-situ synchrotron X-ray diffraction (XRD) was used to monitor the thermal decomposition (thermolysis) of Cd thiolates precursors embedded in a polymer matrix and the nucleation of CdS nanoparticles. A thiolate precursor/polymer solid foil was heated to 300 degrees C in the X-ray diffraction setup of beamline W1.1 at Hasylab, and the diffraction curves were each recorded at 10 degrees C. At temperatures above 240 degrees C, the precursor decomposition is complete and CdS nanoparticles grow within the polymer matrix forming a nanocomposite with interesting optical properties. The nanoparticle structural properties (size and crystal structure) depend on the annealing temperature. Transmission electron microscopy (TEM) and photoluminescence (PL) analyses were used to characterize the nanoparticles. A possible mechanism driving the structural transformation of the precursor is inferred from the diffraction features arising at the different temperatures.  相似文献   

14.
Highly water soluble and biocompatible L-cysteine-capped CdS nanoparticles having narrow size distribution were synthesized for the first time by gamma-irradiation technique without using any additional stabilizer. FTIR study shows that CdS nanoparticles are capped through mercapto-group of cysteine amino acid while its free amino and carboxylate groups make it amenable to bio-conjugation. Size and luminescence of the nanoparticles can be well controlled by varying the parameters like radiation dose, pH and concentration of cysteine. The observed results suggest that pH 7 can be optimum for the synthesis of L-cysteine-capped CdS nanoparticles. CdS nanoparticles synthesized with molar ratio of Cd(2+):cysteine, 1:60 at pH 7 were found to be most luminescent. All nanoparticles formed lie in the size quantization regime and exhibit good crystallinity. Remarkable improvement in stability and luminescence was achieved on changing pH of as-prepared nanoparticles from 7 to 11.  相似文献   

15.
Amphiphilic colloids of CdS and noble metal nanoparticles, which can be dispersed both in water and organic solvents such as ethanol, N,N-dimethylformamide, chloroform, and toluene, are studied. The amphiphilic colloidal nanoparticles are synthesized by grafting the amphiphilic and thermoresponsive polymer of thiol-terminated poly(N-isopropylacrylamide) to CdS and noble metal nanoparticles. The size and morphology of the PNIPAM-grafted colloidal nanoparticles of CdS@PNIPAM can be tuned by changing the molar ratio of PNIPAM/CdS. The size of CdS@PNIPAM nanoparticles slightly decreases first from 5.5 to 4.4 nm then slightly increases from 4.4 to 6.1 nm with the decrease in the molar ratio from 1/1 to 1/10. Spherical nanoparticles of CdS@PNIPAM are synthesized at a higher molar ratio and worm-like nanoparticles are obtained at a lower molar ratio. The resultant PNIPAM-grafted colloidal nanoparticles of CdS@PNIPAM, Au@PNIPAM, Pd@PNIPAM, and Ag@PNIPAM are thermoresponsive in water and show a cloud-point temperature at about 32.5 degrees C.  相似文献   

16.
A new method of reversibly moving CdS nanoparticles in the perpendicular direction was developed on the basis of the phase separation of block copolymer brushes. Polystyrene-b-(poly(methyl methacrylate)-co-poly(cadmium dimethacrylate)) (PS-b-(PMMA-co-PCdMA)) brushes were grafted from the silicon wafer by surface-initiated atom transfer radical polymerization (ATRP). By exposing the polymer brushes to H2S gas, PS-b-(PMMA-co-PCdMA) brushes were converted to polystyrene-b-(poly(methyl methacrylate)-co-poly(methacrylic acid)(CdS)) (PS-b-(PMMA-co-PMAA(CdS))) brushes, in which CdS nanoparticles were chemically bonded by the carboxylic groups of PMAA segment. Alternating treatment of the PS-b-(PMMA-co-PMAA(CdS)) brushes by selective solvents for the outer block (a mixed solvent of acetone and ethanol) and the inner PS block (toluene) induced perpendicular phase separation of polymer brushes, which resulted in the reversible lifting and lowering of CdS nanoparticles in the perpendicular direction. The extent of movement can be adjusted by the relative thickness of two blocks of the polymer brushes.  相似文献   

17.
水热法合成CdS/ZnO核壳结构纳米微粒   总被引:31,自引:0,他引:31  
以半胱氨酸镉配合物为前驱体,采用水热法合成CdS纳米微粒,并以ZnO对其进行表面修饰,形成具有核/壳结构的CdS/ZnO半导体纳米微粒,CdS纳米微粒表面经ZnO修饰后,其带边发射大大增强,透射电镜显示,110℃下反应4h所得的CdS/ZnO颗粒尺寸约为20nm,电子衍射表明其结构为六方相。  相似文献   

18.
In the present work, it is reported for the first time the bioconjugation of CdS quantum dots (QDs) directly with bovine serum albumin (BSA) using a one-step procedure via aqueous route at room temperature by methods of colloidal chemistry. Essentially, the bioconjugates were developed based on BSA as capping ligand for the nucleation and stabilization of CdS nanoparticles using cadmium perchlorate and thioacetamide as precursors. UV-visible spectroscopy was used to characterize the kinetics and the relative stability of CdS nanoparticles. The CdS nanocrystals were produced with the calculated average particle size below 4.0 nm, indicating they were in the so-called "quantum-size confinement range". The results have clearly indicated that BSA was effective on nucleating and stabilizing the colloidal CdS quantum dots.  相似文献   

19.
以AOT为保护剂,采用反胶束法合成CdS纳米粒子。利用水洗法洗去保护剂AOT,通过加入不同量的无水乙醇调节分散介质的极性,改变CdS纳米粒子在分散介质中的"溶解度",从而实现不同尺寸粒子的分离。采用紫外-可见(UV-vis)吸收光谱、透射电子显微镜(TEM)、荧光光谱法对其进行表征。  相似文献   

20.
A film polymer nanocomposite with nanoparticles of a chalcogenide semiconductor, CdS, in a polystyrene matrix was prepared on the surface of 08kp steel. The barrier properties of the synthesized two-layer film nanomaterial in a 3 wt % aqueous NaCl solution were evaluated by measuring the electrode potential of coated and uncoated specimens and were compared with those of polymer films without nanofiller and with Fe3O4 nanoparticles. Introduction of hydrophobic CdS nanoparticles into the polymer matrix leads to significant enhancement (by ~20%, as compared to Fe3O4) of the barrier properties of the polymer nanocomposite.  相似文献   

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