模板浸润法制备聚苯乙烯纳米管阵列

采用一种简单的物理技术——聚合物溶液或熔体浸润多孔阳极氧化铝(AAO)模板的方法,在孔径仅为200nm的AAO模板中制备聚苯乙烯(PS)纳米管阵列。SEM和TEM测试结果表明：熔体法制备的纳米管壁厚约为110nm;5．0wt％和10．0wt％的PS溶液制备的纳米管壁厚分别为70nm和80nm。并初步探索了模板法制备聚合物纳米管的多次浸润机理。     

聚合物一维纳米材料的研究进展

综述了聚合物纳米线和纳米管等聚合物一维纳米材料的制备方法、机理和应用。聚合物纳米线的制备方法主要有静电纺丝法、多孔模板法、自组装法三种。聚合物纳米管的制备包括多孔模板法、线模板法、自组装法等方法。本文评述了其研究现状,展望了其可能的应用前景。     

模板浸润法制备聚合物纳米管阵列

以孔径为200nm的多孔氧化铝膜（AAO）为模板、常规分子量的通用聚合物为原料,采用聚合物溶液或熔体浸润模板纳米孔的物理技术,进行了多种聚合物纳米管的制备研究。结果表明：聚苯乙烯、尼龙66、聚丙烯、ABS、热塑性聚氨酯等多种聚合物纳米管及其纳米管阵列成功制得。运用扫描电子显微镜（SEM）和透射电子显微镜（TEM）观察了纳米管的微观形貌和阵列结构。并探讨了聚合物性质、纳米管制备工艺与纳米管结构的关系,初步探索了多孔模板法制备聚合物纳米管的机理。     

多孔模板法制备热塑性聚氨酯(TPU)纳米管

采用聚合物溶液和熔体浸润多孔阳极氧化铝（AAO）模板的物理方法,成功制备了通孔的热塑性聚氨酯（TPU）纳米管及其阵列结构．扫描电子显微镜（SEM）和透射电子显微镜（1EM）测试表明：有效地调整溶液滴加量可制备出不同结构的聚合物纳米管阵列．以浓度为7．0％（wt）TPU溶液为例,研究了溶液滴加量对纳米管结构之间的关系,2μL为制得TPU纳米管阵列结构的最佳滴加量．并探索首次浸润程度对纳米管结构的影响,完善了模板浸润法的多次浸润机理．     

ZrO2纳米管的溶胶-凝胶模板法制备与结构表征

用溶胶-凝胶法在多孔阳极氧化铝模板中制备了ZrO2纳米管.通过SEM和TEM表征了ZrO2纳米管的形貌,用选区电子衍射和XRD研究了ZrO2纳米管的晶体结构,FT-IR分析了zrO2纳米管的键合结构.结果表明,所制备的纳米管阵列高度有序,管径和长度分别与AAO模板的孔径和厚度相当;纳米管管壁的厚度随浸泡时间增加而增厚,可通过控制浸泡时间等因素来制备不同孔径的纳米管或线.ZrO2纳米管为单斜晶和立方晶形的多晶结构;纳米管的形成机理是溶胶粒子在AAO模板孔壁酸位上的吸附.     

聚合物泡孔材料为模板的溶胶-凝胶法

采用浓乳液聚合方法制备出多孔聚合物结构材料作为模板,通过溶胶-凝胶法,将异丙醇钛的异丙醇溶液多次浸泡聚合物泡孔材料制备出了尺寸为毫米级的多孔氧化钛陶瓷材料.考察了多孔性的聚合物模板的孔径对所制备陶瓷孔径的影响,以及不同聚合物模板体系对陶瓷结构的影响,并采用扫描电子显微镜对所制备的陶瓷材料进行了形态表征.结果表明,通过调节浓乳液体系分散相的体积分数以及改变聚合物模板体系均可以有效地调节所制备的多孔陶瓷的形态结构.     

模板法制备聚乙烯咔唑纳米结构中的浸润转变

采用溶液浸润多孔阳极氧化铝模板(AAO)的方法,在孔径为200nm的AAO模板中制备功能聚合物聚乙烯咔唑(poly(vinyl carbazole),PVK)一维纳米结构.SEM和TEM测试结果表明,2.5%和3.5%(质量分数)的PVK溶液可制得纳米管,其外径约为200nm,管壁厚度分别为30与70nm;而5.0%与10.0%(质量分数)的PVK溶液可制得纳米线,其直径约为200nm.提出了溶液浸润模板法中的完全浸润体系和部分浸润体系以及临界浸润浓度Cw.     

阳极氧化铝样模法制备纳米线阵列的发展概况

对金属纳米线的研究和发展进行了回顾和展望:在多孔阳极氧化铝模板上可制备出不同直径和长度的纳米管或纳米线阵列;所制备的纳米线有着光、电、磁、催化等特性,具有广泛的用途及发展前景.     

多孔氧化铝模板结合sol-gel旋转涂敷法制备PZT纳米管

利用溶胶-凝胶旋转涂敷法在通孔的多孔阳极氧化铝(PAA)模板中制备了锆钛酸铅(PZT)纳米管,研究了溶胶浓度对样品形貌的影响。利用SEM和TEM观察了纳米管阵列和单根纳米管的形貌,采用XRD和EDS图谱分析了纳米管的相结构和化学元素组成。结果表明合成的PZT纳米管结晶良好,具有钙钛矿结构(属于四方晶系);纳米管具有较高的韧性但表面较粗糙,直径和管壁厚度分别约为75和7nm,直径与原始PAA模板的孔径相吻合。在一定范围内调节PZT溶胶的浓度(0.1～0.4mol/L),均能在PAA模板的孔洞中形成PZT多晶纳米管,且组成PZT纳米管的晶粒随着溶胶浓度的增加而变大。     

氮掺杂二氧化钛纳米管制备与光催化性能

以多孔氧化铝为模板,采用溶胶凝胶法制备出二氧化钛纳米管,在氨气气氛下进行了氮掺杂。用TEM、XRD、DRS等对其进行了表征,并通过降解碱性藏花红溶液研究了其光催化的性能。结果表明,用模板法制备的二氧化钛纳米管管径均匀、可控且排向一致,从DRS光谱可以推测出氮掺杂后的二氧化钛纳米管在可见光区有较强的吸收,并且与二氧化钛纳米管相比氮掺杂的二氧化钛纳米管的降解碱性藏花红溶液的效率更高。     

Ni纳米管的电化学模板法制备及表征

本文采用一种简单而有效的电化学方法在硫酸铵体系中利用氧化铝模板(AAO)成功制备出规则有序的Ni的管状纳米阵列.使用这种方法可获得外径约为70nm,内径约为50nm的Ni纳米管.对所得的Ni纳米管进行了扫描电镜(SEM)、透射电镜(TEM)、选区电子衍射图(SAED)和X射线衍射(XRD)分析,结果表明:该方法制备的Ni纳米管高度有序,大小均一,其形貌受控于氧化铝模板的结构,外径与模板的孔径相等.     

溶液浸润模板法制备图案化ABS纳米管阵列

采用紫外光刻技术首先制备了图案化的阳极氧化铝(AAO)模板,以此作为"二次模板",以不同浓度的ABS溶液浸润模板,成功地制备了不同结构的ABS纳米管阵列。用扫描电镜(SEM)对其微观形貌进行表征,结果显示,所获得的ABS纳米管阵列排列规整,高度有序,与掩膜的图案完全一致。并且讨论了溶液浓度对纳米管壁厚的影响。     

原位合成TiO2纳米管阵列及其光催化性能研究

采用液相沉积法(LPD), 以阳极氧化铝(AAO)为模板, 原位合成高度有序的TiO₂纳米管薄膜材料. 实验结果表明, 经过400℃热处理后, 制备的TiO₂纳米管为锐钛矿相, 长度达5μm, 管外径为150nm左右, 管壁厚为25nm左右. 热处理后的TiO₂薄膜具有良好的光催化降解甲基蓝的性能, 即经过120min卤灯照射后, 甲基蓝被完全降解.     

Instabilities in nanoporous media

Rayleigh instabilities in thin polymer films confined within nanoporous alumina membranes were studied. Thin films of poly(methyl methacrylate) (PMMA) were prepared by filling cylindrical nanopores in an anodic aluminum oxide (AAO) membrane with a PMMA solution in chloroform followed by solvent evaporation. When the PMMA nanotubes were annealed above the glass transition temperature (Tg), undulations in the film thickness were observed that were induced by a Rayleigh instability. The amplitude of the undulations increased with time and eventually bridged across the cylindrical nanopore in the AAO membrane, resulting in the formation of polymer nanorods with periodic encapsulated holes. A similar behavior was observed when PMMA films were confined within carbon nanotubes (CNTs). The Rayleigh instabilities in these confined geometries offer a novel means of controlling and fabricating the polymer nanostructures. These compartmentalized nanorods may have potential applications as delivery devices.     

Fabrication, structural characterization and formation mechanism of multiferroic BiFeO3 nanotubes

Multiferroic BiFeO3 (BFO) nanotubes have been successfully fabricated by the modified sol-gel method within the nanochannels of porous anodic aluminum oxide (AAO) templates. The morphology, structure and composition of the nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), selected-area electron diffraction (SAED), high resolution TEM, (HRTEM) and energy-dispersive X-ray spectroscopy (EDX). Postannealed (650 degrees C for 1 h), BFO nanotubes were polycrystalline and X-ray diffraction study revealed that they are of the rhomohedrally distorted perovskite crystal structure. The results of SEM and TEM revealed that BFO nanotubes possessed a uniform length (up to 60 microm) and diameter (about 200 nm), which were controlled by the thickness and the pore diameter of the applied AAO template, respectively and the thickness of the wall of the BFO nanotube was about 15 nm. Y-junctions in the BFO nanotubes were observed. EDX analysis demonstrated that stoichiometric BiFeO3 was formed. HRTEM analysis confirmed that the obtained BFO nanotubes made up of nanoparticles (3-6 nm). The possible formation mechanism of BFO nanotubes was discussed.     

A template-based electrochemical method for the synthesis of high dense nickel nanotube arrays

High dense Ni nanotube arrays have been successfully fabricated using electrochemical method with the assistance of anodic aluminum oxide (AAO) template from NiSO4 aqueous solution without any additive. Field emission scanning electron microscope (FE-SEM) results indicate that the pores of AAO template are high uniform and all the pores are filled with Ni nanotubes. Transmission electron microscope (TEM) results demonstrate that the diameter of Ni nanotubes is about 65 nm. The electron diffraction (ED) pattern results show that the Ni nanotubes are polycrystalline. X-ray diffraction (XRD) pattern shows that the electrodeposited nickel is hexagonal crystal structure.     

Preparation and characterization of yttria-stabilized zirconia nanotubes

Yttria-stabilized zirconia (YSZ) nanotubes were synthesized by the sol–gel method using porous anodic alumina oxide (AAO) as the templates. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersion X-ray (EDX) spectrum and selected area electron diffraction (SAED) techniques were used to characterize the morphology and crystalline structure of the prepared YSZ nanotubes. The length and the diameter of the YSZ nanotubes are 50 μm and 200 nm, respectively, which are in good agreement with the dimensions of the template pores, while the wall thickness of the nanotubes depends on the impregnation time. XRD and SAED measurements indicate that the obtained YSZ nanotubes after sintering at 1073 K possess a polycrystalline structure and a cubic crystal phase. Brunauer–Emmett–Teller (BET) measurement shows that the YSZ nanotubes have a surface specific area of around 40.5 m² g⁻¹ that is higher than that corresponding to the YSZ nanopowders.     

Fabrication of ordered magnetite-doped rare earth fluoride nanotube arrays by nanocrystal self-assembly

We describe a nanocrystal self-assembly method for the preparation of rare earth fluoride nanotube (ReF-NT) arrays and magnetite-doped rare earth fluoride nanotubes (Fe₃O₄-ReF-NTs) by using porous anodic aluminum oxide (AAO) as a hard template. The ReF-NTs can be simply prepared by the impregnation of α-NaYF₄ nanocrystals doped with Yb and Er into the channels of the porous AAO and show a highly ordered nanotube array and excellent upconversion (UC) fluorescence properties. Similarly, the Fe₃O₄-ReF-NTs are obtained by the self-assembly of a mixture of Fe₃O₄ and Yb/Er doped α-NaYF₄ nanocrystals in the AAO pore channels and have a uniform dispersion of magnetite nanocrystals on the rare earth fluoride tube matrix and possess multifunctional magnetic/UC properties. The diameter of these nanotubes can be varied from 60 nm to several micrometers depending on the pore size of the AAO template. The wall thickness can be increased from 10 to 35 nm by increasing the concentration of nanocrystals from 0.02 to 0.4 mmol/L, while the morphology of the nanotubes can be varied from small isolated domain structures to percolating domains and eventually to compact domains. A template-directed formation mechanism is proposed and the quantitative predictions of the model for such self-assembled nanocrystal spreading processes are demonstrated. Strong UC fluorescent emissions are realized for the nanotube arrays and multifunctional nanotubes with UC excitation in the near-infrared (NIR) region. A strong magnetic response of the multifunctional nanotubes is observed, which facilitates their easy separation from solution by magnetic decantation using a permanent magnet.     

Template-mediated synthesis and bio-functionalization of flexible lignin-based nanotubes and nanowires

Limitations of cylindrical carbon nanotubes based on the buckminsterfullerene structure as delivery vehicles for therapeutic agents include their chemical inertness, sharp edges and toxicological concerns. As an alternative, we have developed lignin-based nanotubes synthesized in a sacrificial template of commercially available alumina membranes. Lignin is a complex phenolic plant cell wall polymer that is generated as a waste product from paper mills and biorefineries that process lignocellulosic biomass into fuels and chemicals. We covalently linked isolated lignin to the inner walls of activated alumina membranes and then added layers of dehydrogenation polymer onto this base layer via a peroxidase-catalyzed reaction. By using phenolic monomers displaying different reactivities, we were able to change the thickness of the polymer layer deposited within the pores, resulting in the synthesis of nanotubes with a wall thickness of approximately 15?nm or nanowires with a nominal diameter of 200?nm. These novel nanotubes are flexible and can be bio-functionalized easily and specifically, as shown by in vitro assays with biotin and Concanavalin A. Together with their intrinsic optical properties, which can also be varied as a function of their chemical composition, these lignin-based nanotubes are expected to enable a variety of new applications including as delivery systems that can be easily localized and imaged after uptake by living cells.     

Synthesis and characterization of TiO2/WO3 composite nanotubes for photocatalytic applications

TiO₂/WO₃ composite nanotubes were synthesized in an anodic aluminum oxide (AAO) template by a sol–gel method. The prepared nanotubes were characterized by transmission electron microscopy, scanning electron microscopy, powder X-ray diffraction, and Brunauer–Emmett–Teller surface area. Using the nanotubes embedded in the AAO templates as catalysts, photocatalytic degradation of methyl orange aqueous solution was carried out under UV light irradiation. The results showed that the TiO₂/WO₃ composite nanotubes with the thickness about 50 nm could be successfully synthesized by this method. TiO₂ showed anatase phase and WO₃ displayed monoclinic phase. The composite nanotubes (TiO₂/WO₃) exhibited higher photocatalytic activity than the pure nanotubes (WO₃ or TiO₂). The possible reason for improving the photocatalytic activity was also discussed.