共查询到19条相似文献,搜索用时 109 毫秒
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棒状线圈三嵌段共聚物的液晶超分子结构研究进展 总被引:1,自引:1,他引:0
如何获得能形成纳米尺寸的新型超分子材料以及研究这些结构对材料性质的影响成为当今分子设计的热点。由刚性芳香核(棒状Rod:B)及柔性链(线圈状Coil:A或C)组成的棒状线圈三嵌段共聚物能在纳米尺度上自组装出丰富多彩的纳米液晶超分子结构。介绍了不对称ABC(Coil-Rod-Coil)、对称ABA(Coil-Rod-Coil)及BAB(Rod-Coil-Rod)棒状线圈三嵌段共聚物的液晶超分子行为,讨论了疏水性作用力、各嵌段体积大小、分子形状、分子长度等结构因素的改变对这类三嵌段共聚物液晶分子自组装结构的影响,介绍了棒状线圈三嵌段共聚物组装形成的一序列一维层列相、二维柱相及三维的立方、四方相等多种连续的及不连续的复杂纳米液晶超分子结构。 相似文献
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以嵌段聚醚氨基硅(BPEAS)、马来酸酐为原料合成了羧基改性的嵌段聚醚氨基硅(MAn-BPEAS),用红外光谱(IR)对产物结构进行表征。用非离子表面活性剂异构醇聚氧乙烯醚(XL)将BPEAS与MAn-BPEAS乳化,制得外观半透明乳液。在自组装理论的指导下,将制得的乳液等质量混合进行静电自组装,得到超分子乳液。利用纳米粒度表面电位分析仪测定了自组装前后的乳液中胶束的粒径。将制得的超分子乳液应用于织物整理,并通过扫描电镜观察织物表面的膜形貌。考察了BPEAS、MAn-BPEAS及其超分子乳液在棉织物上的应用性能。 相似文献
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Pluronic嵌段共聚物胶束化行为及其胶束增溶 总被引:2,自引:0,他引:2
两亲性质的Pluronic嵌段共聚物在合适条件下能自发形成内核很大的稳定胶束 ,其胶束化行为复杂 ,初步的研究深化了对两亲分子自组织机理的认识。实验发现这类胶束具有很强的增溶油溶性物质的能力 ,由于这些分子单体和胶束化行为的特点 ,可望利用这类嵌段共聚物实现在增溶应用场合中的突破。综述Pluronic嵌段共聚物的胶束化行为和胶束增溶规律的当前研究进展 相似文献
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聚氧乙烯-聚氧丙烯-聚氧乙烯(PEO-PPO-PEO)嵌段共聚物是一类重要的非离子表面活性剂,在选择性溶剂中可以自组装成多种形貌的介观结构。对PEO-PPO-PEO嵌段共聚物在水溶液中自组装行为进行了综述,介绍了其自组装行为的实验研究技术;阐明了嵌段共聚物构型、分子量、温度、浓度、添加剂等因素对PEO-PPO-PEO嵌段共聚物聚集行为的调控和作用机理;介绍了嵌段共聚物自组装特性的热力学模型、分子模拟及计算机预报等研究方法和研究进展;重点介绍了PEO-PPO-PEO嵌段共聚物在介孔材料制备、药物载体、生物大分子分离、嵌段共聚物修饰等方面的应用。 相似文献
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基于Martini力场采用粗粒化分子动力学模拟研究了Pluronic嵌段共聚合物在疏水纳米表面自组装膜结构,考察了Pluronic嵌段共聚合物结构对自组装单分子膜结构的影响。模拟结果发现Pluronic聚合物在疏水纳米表面自组装形成了以纳米材料为核,聚合物为壳的特殊核-壳结构。聚合物的浓度和结构都会影响该壳层结构,在浓度较低时,聚合物EO嵌段卷曲地附着在疏水纳米颗粒表面,类似形成层状的壳层结构;随着浓度的提高,EO嵌段伸向溶剂相,形成星形自组装膜结构。增加Pluronic共聚物相对分子质量,吸附在纳米材料的聚合物壳层厚度也逐渐增加。随着聚合物PO摩尔的增加,吸附在纳米材料表面的PO嵌段由“S”形或“W”形吸附逐渐变成“U”形吸附。这可能因为随着聚合物浓度的提高,有限的纳米颗粒表面不足以提供足够多的吸附位点导致聚合物吸附构型转变。 相似文献
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基于Martini力场采用粗粒化分子动力学模拟研究了Pluronic嵌段共聚合物在疏水纳米表面自组装膜结构,考察了Pluronic嵌段共聚合物结构对自组装单分子膜结构的影响。模拟结果发现Pluronic聚合物在疏水纳米表面自组装形成了以纳米材料为核,聚合物为壳的特殊核-壳结构。聚合物的浓度和结构都会影响该壳层结构,在浓度较低时,聚合物EO嵌段卷曲地附着在疏水纳米颗粒表面,类似形成层状的壳层结构;随着浓度的提高,EO嵌段伸向溶剂相,形成星形自组装膜结构。增加Pluronic共聚物相对分子质量,吸附在纳米材料的聚合物壳层厚度也逐渐增加。随着聚合物PO摩尔的增加,吸附在纳米材料表面的PO嵌段由"S"形或"W"形吸附逐渐变成"U"形吸附。这可能因为随着聚合物浓度的提高,有限的纳米颗粒表面不足以提供足够多的吸附位点导致聚合物吸附构型转变。 相似文献
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本文利用阳极氧化法在纯钛片表面制备了TiO2纳米管阵列膜,解决TiO2光催化剂的涂敷固定问题。采用场发射扫描电镜(FESEM)和XRD对制备TiO2纳米管阵列膜的形貌和晶体结构进行表征。结果发现,所制得的纳米管管径70~80nm,壁厚5~10nm,XRD显示经420℃热处理的TiO2纳米管为锐钛矿晶型,经500℃热处理的TiO2纳米管出现金红石晶型。以10mg·L-1的甲基橙溶液为降解物进行光催化试验,分别研究了溶液的初始pH值、TiO2纳米管阵列膜的晶型、TiO2膜的使用次数对降解率的影响。试验结果表明,当溶液初始pH值为1时,TiO2纳米管阵列的光催化性能最好,同时随着TiO2膜使用次数的增加,其光催化效果有所下降。 相似文献
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Based on the self-ordering behavior of ionic liquids on solid surface, a gold ion containing ionic liquid was employed to obtain a uniform pattern of gold nanoparticles on Si substrate. Using this catalytic pattern, super-dense, centimetre long, well-crystallized and vertically-aligned ZnS nanowire arrays were then generated. It was found that the densely-packed gold nanoparticles played a key role in the nanowire alignment. Furthermore, the field-emission measurements show that the present ultralong ZnS nanowires arrays possess a low turn-on field of 3.69 V μm(-1) and a high field-enhancement factor of 1215.4, indicating they are valuable field emitters. 相似文献
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Single wall carbon nanotubes are dispersed in water with the water-soluble polymer polyvinylpyrrolidone and the surfactant sodium dodecylbenzene sulfonate, and then deposited by evaporative deposition onto degeneratively-doped silicon wafer substrates. These deposits were examined by scanning electron microscopy, which revealed highly-ordered arrays of large single wall carbon nanotube bundles. Various solution concentrations were prepared and deposition conditions were varied to determine their affect on the single wall carbon nanotube arrays. These observations were related to existing lyotropic liquid crystal theory and theories explaining the behavior of carbon nanotubes in solution, which allowed for further development and interpretation of the phase diagram which describes the behavior of single wall carbon nanotubes in lyotropic liquid crystal systems, and how competing liquid crystal systems in the same solution directly affect the ordering of the single wall carbon nanotube arrays. 相似文献
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采用电化学阳极氧化的方法,以氟化铵水溶液为电解液,在纯钛表面制备了TiO2纳米管阵列。以甲基橙为模拟污染物,考察了TiO2纳米管阵列光催化降解效果。结果表明,TiO2纳米管阵列催化降解效果要好于TiO2薄膜电极,60、120和180 min时,降解率分别为56%、88%和100%;而TiO2薄膜电极的降解率分别为43%、76%和91%。在此基础上,考察了阳极氧化电压、氧化时间和焙烧温度对阳极氧化过程的影响规律。结果表明,阳极氧化电压在10~25 V,氧化时间在1~2 h,焙烧温度在500℃时所制备的TiO2纳米管阵列光催化降解性能最好。 相似文献
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Slavomír Nemšák Evgheni Strelcov Hongxuan Guo Brian D. Hoskins Tomáš Duchoň David N. Mueller Alexander Yulaev Ivan Vlassiouk Alexander Tselev Claus M. Schneider Andrei Kolmakov 《Topics in Catalysis》2018,61(20):2195-2206
Recent developments in environmental and liquid cells equipped with electron transparent graphene windows have enabled traditional surface science spectromicroscopy tools, such as scanning X-ray photoelectron microscopy, X-ray photoemission electron microscopy (XPEEM), and scanning electron microscopy to be applied for studying solid–liquid and liquid–gas interfaces. Here, we focus on the experimental implementation of XPEEM to probe electrified graphene–liquid interfaces using electrolyte-filled microchannel arrays as a new sample platform. We demonstrate the important methodological advantage of these multi-sample arrays: they combine the wide field of view hyperspectral imaging capabilities from XPEEM with the use of powerful data mining algorithms to reveal spectroscopic and temporal behaviors at the level of the individual microsample or the entire array ensemble. 相似文献
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We show that the substrate affects the interparticle spacing in monolayer arrays with hexagonal order formed by self-assembly of polymer grafted nanoparticles. Remarkably, arrays with square packing were formed due to convective shearing at a liquid surface induced by miscibility of colloidal solution with the substrate. 相似文献
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Kenis PJ Ismagilov RF Takayama S Whitesides GM Li S White HS 《Accounts of chemical research》2000,33(12):841-847
This Account summarizes techniques for carrying out microfabrication of structures with dimensions down to 10 microm in microchannels that are 0.02-2 mm wide. These methods are largely based on the exploitation of laminar flow at low Reynolds number (Re) to control the spatial delivery of reagents. These methods are illustrated by fabrication of fibers, microelectrode arrays, arrays of crystals, and patterns of proteins and cells. 相似文献
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A novel vapor-liquid-solid epitaxy (VLSE) process has been developed to synthesize high-density semiconductor nanowire arrays. The nanowires generally are single crystalline and have diameters of 10-200 nm and aspect ratios of 10-100. The areal density of the array can readily approach 1010 cm-2. Results based on Si and ZnO nanowire systems are reported here. Because of their single crystallinity and high surface area, these nanowire arrays could find unique applications in photocatalysis and photovoltaics. 相似文献