氨基化多壁碳纳米管的制备与表征

以多壁碳纳米管(MWNTs)为原料, 经自由基反应, 制备了氰基改性的多壁碳纳米管, 然后采用Al-NiCl₂·6H₂O-THF体系还原氰基得到了氨基化的碳纳米管。通过拉曼光谱仪、热重分析仪、X射线光电子能谱仪和透射电子显微镜对产物的结构与形貌进行了表征。结果表明:氨基通过共价键枝接在MWNTs的表面, 氨基化多壁碳纳米管每1000个表面碳原子中有17.1个转化为氨基;该反应条件温和, 反应时间短, 且不破坏MWNTs的结构。     

高性能环氧树脂/碳纳米管复合物的热分析研究

用差示扫描量热仪(DSC)、热失重分析仪(TGA)和动态力学热分析仪(DMTA)研究了多壁碳纳米管(MWNTs)/高性能4,4′-二氨基二苯甲烷四缩水甘油环氧树脂(TGDDM)/4,4′-二氨基二苯基砜(DDS)复合物的热性能.Kissinger和Flynn-Wall-Ozawa的非等温固化动力学研究发现,随着MWNTs含量的增加,复合物固化反应的活化能先减小后增大.TGA研究表明,MWNTs的添加对环氧树脂热稳定性影响很小.碳纳米管填充到TGDDM/DDS体系后,复合物的储存模量随着MWNTs含量的增加而增大,而玻璃化温度却随之减小.     

非离子表面活性剂对多壁碳纳米管在乙醇中高浓度分散的作用

如果能在无需聚合物或共价官能团辅助的条件下, 将多壁碳纳米管(MWNTs)高浓度地分散在乙醇中, 那么向各种复合材料引入MWNTs的过程就会更加便捷. 为此, 制备了多种含有表面活性剂的多壁碳纳米管乙醇悬浮液并对比考查了它们的稳定性. 非离子表面活性剂Triton X-100 和Tween 65显示出了在乙醇中分散悬浮高浓度MWNTs的能力, 能够使1.0 g·L-1 MWNTs乙醇悬浮液的上层清液经240 h后浓度仍分别在0.50和0.35 g·L-1以上. 这样长时间稳定的、没有聚合物或共价官能团辅助的MWNTs乙醇悬浮液, 其浓度比文献报道的值高. 进一步探讨了这些非离子表面活性剂分子结构对于分散MWNTs的优势, 并直观给出了其吸附于碳纳米管表面的可能形式. X射线光电子能谱和透射电子显微镜的表征结果都证实了表面活性剂分子吸附于碳纳米管表面.     

聚合物对多壁碳纳米管的包覆改性研究

探讨了聚合物对碳纳米管的包覆改性.将多壁碳纳米管(MWNTs)通过浓硫酸和浓硝酸的混酸(体积比=3∶1)处理,使其带上羧基.将羧化MWNTs与甲基丙烯酸缩水甘油酯(GMA),苯乙烯双组分接枝聚苯乙烯(PS-g-(GMA-co-St))通过溶液共混方法,使其接在MWNTs上的羧基和GMA所带的环氧基团之间发生酯化反应,实现MWNTs表面接枝上PS-g-(GMA-co-St).扫描电镜观察表明,羧化MWNTs平均管径约为40nm,而接枝上PS-g-(GMA-co-St)的改性MWNTs管径可达约100nm.用四氢呋喃(THF)对表层包覆的PS-g-(GMA-co-St)刻蚀后,其直径降回到约40nm,这和先前观察到的羧化MWNTs的直径基本一致.对刻蚀后的MWNTs样品的FT-IR分析也表明MWNTs表面上存在接枝PS.表面经过PS-g-(GMA-co-St)修饰后,可以形成包覆层,为MWNTs在聚合物基体中分散、制备纳米功能材料提供了途径.     

氨基卟啉共价化学修饰多壁碳纳米管

合成了5-(4-氨基)苯基-10,15,20-三苯基卟啉及其铜配合物, 通过化学键将氨基卟啉与活化的多壁碳纳米管(MWNT)发生酰胺化反应, 从而得到卟啉有机共价化学修饰的多壁碳纳米管的复合物. 通过红外光谱对产物的化学结构进行了表征, 证实了复合物体系中酰胺反应的发生. 紫外可见光吸收光谱和荧光光谱分析确定了卟啉与多壁碳纳米管间存在强烈的电子效应. 通过透射电镜(TEM)观察了产物的形貌特征, 发现碳纳米管壁上连接上了氨基卟啉小分子, 进一步证实了酰胺化反应的发生.     

聚乙烯基吡咯烷酮修饰多壁碳纳米管的研究

采用超声波辅助技术,研究了两亲性聚合物聚乙烯基吡咯烷酮(PVP)修饰多壁碳纳米管(MWNTs)的效果、作用机理及影响因素.研究结果表明在适合的条件下两亲性聚合物PVP可以被引入到多壁碳纳米管表面,修饰后的MWNTs在DMF、乙醇和水等溶剂中具有良好的分散性.通过红外光谱(FTIR)和拉曼光谱(Raman)分析表明,两亲性聚合物与MWNTs之间产生了化学接枝作用,高分辨透射电镜分析表明两亲性聚合物不均匀地存在于MWNTs的表面和端部.两亲性聚合物的浓度对接枝量的影响不大,但超声波作用时间对MWNTs表面两亲性聚合物PVP的接枝量有较大的影响,在超声时间为4h时接枝量最大.两亲性聚合物修饰效果不同于表面活性剂,采用表面活性剂十二烷基苯磺酸钠(SDBS)修饰的MWNTs经过洗涤过滤后,不能重新溶于水中,而两亲性聚合物PVP修饰的MWNTs可以重新溶解.     

聚(2,5-苯并(口恶)唑)/多壁碳纳米管复合材料的制备与性能

采用强氧化性酸处理多壁碳纳米管(MWNTs),形成功能化的多壁碳纳米管(MWNTs-COOH)。用傅里叶红外光谱(FT-IR)对处理前后MWNTs的表面官能团进行了分析,并利用原位聚合法成功制备了聚(2,5-苯并噁唑)(ABPBO)/MWNTs-COOH纳米复合材料。结果表明:碳纳米管经过酸处理后,表面含有较多羰基和羟基极性官能团,在ABPBO基体中分散均匀;复合材料保持了ABPBO的优异耐高温性能,其力学性能和光物理性能也得到了很大的提高。     

聚(2,5-苯并噁唑)/多壁碳纳米管复合材料的制备与性能

采用强氧化性酸处理多壁碳纳米管(MWNTs),形成功能化的多壁碳纳米管(MWNTs-COOH)。用傅里叶红外光谱(FT-IR)对处理前后MWNTs的表面官能团进行了分析,并利用原位聚合法成功制备了聚(2,5-苯并噁唑)(ABPBO)/MWNTs-COOH纳米复合材料。结果表明:碳纳米管经过酸处理后,表面含有较多羰基和羟基极性官能团,在ABPBO基体中分散均匀;复合材料保持了ABPBO的优异耐高温性能,其力学性能和光物理性能也得到了很大的提高。     

多壁碳纳米管功能化及其在电化学葡萄糖传感器中的应用

利用硅烷偶联剂的表面修饰技术,将氨基丙基三乙氧基硅烷(APS)共价接枝到酸处理后的碳纳米管的表面.红外光谱数据证实了该反应的可行性.修饰后的碳纳米管在水中具有良好的分散性.利用西夫碱反应将氨基化的碳纳米管与醛基化的葡萄糖氧化酶共价层层自组装到电极表面,获得灵敏度可控的葡萄糖传感器.用电化学交流阻抗法和扫描电镜对成膜过程...     

多壁碳纳米管表面L-组氨酸手性印迹聚合材料的制备及性能表征

通过酰胺化反应在多壁碳纳米管（MWNTs）表面接枝双键,以L-组氨酸（L-His）为模板,甲基丙烯酸（MAA）为功能单体,乙二醇二甲基丙烯酸酯（EGDMA）为交联剂,偶氮二异丁腈（AIBN）为引发剂,利用表面印迹技术,在MWNTs表面制备印迹聚合物（MWNTs-MIPs）．采用红外光谱,扫描电子显微镜和热重分析表征印迹聚合物的性质,结果表明MWNTs表面成功接枝了一层稳定的、厚度为35～40nm具有识别能力的印迹聚合材料．结合高效液相色谱技术,通过填充色谱柱在线色谱分析,探讨不同pH值的流动相下该印迹材料对L-His的分离行为,结果表明MWNTs—MIPs色谱柱在流动相pH=7．0时分离效果最好,能够选择性地识别L-His和D-His,分离度R为1．78,选择因子α为1．28．     

Composite film of carbon nanotubes and chitosan for preparation of amperometric hydrogen peroxide biosensor

A new amperometric biosensor for hydrogen peroxide was developed based on cross-linking horseradish peroxidase (HRP) by glutaraldehyde with multiwall carbon nanotubes/chitosan (MWNTs/chitosan) composite film coated on a glassy carbon electrode. MWNTs were firstly dissolved in a chitosan solution. Then the morphology of MWNTs/chitosan composite film was characterized by field-emission scanning electron microscopy. The results showed that MWNTs were well soluble in chitosan and robust films could be formed on the surface. HRP was cross-linked by glutaraldehyde with MWNTs/chitosan film to prepare a hydrogen peroxide biosensor. The enzyme electrode exhibited excellent electrocatalytic activity and rapid response for H₂O₂ in the absence of a mediator. The linear range of detection towards H₂O₂ (applied potential: −0.2 V) was from 1.67 × 10⁻⁵ to 7.40 × 10⁻⁴ M with correction coefficient of 0.998. The biosensor had good repeatability and stability for the determination of H₂O₂. There were no interferences from ascorbic acid, glucose, citrate acid and lactic acid.     

单斜与锐钛矿双晶相TiO2/MWNTs复合材料的制备及其可见光光催化活性

以超强耐酸碱的表面活性剂-丁基封端脂肪醇聚氧乙烯醚作为晶型调节剂,利用钛酸丁酯和氢氧化钠的水热反应制备了单斜相与锐钛矿相双晶相TiO₂/多壁碳纳米管(简称MWNTs)复合材料,并考察了复合材料的可见光光催化活性。结果显示:MWNTs的加入可调控TiO₂的晶相组成,增强TiO₂的光催化活性,其中含5%MWNTs的样品具有较高的催化降解效率;随煅烧温度的升高,样品的光催化活性大幅提升。其机理归因于(1)促进单斜相和锐钛矿相双晶相结构的形成;(2)碳纳米管优良的导电作用及碳纳米管/TiO₂间的异质结效应;(3)高温下碳纳米管分解产生的碳元素掺杂作用。     

单斜与锐钛矿双晶相TiO2/MWNTs复合材料的制备及其可见光光催化活性

以超强耐酸碱的表面活性剂-丁基封端脂肪醇聚氧乙烯醚作为晶型调节剂,利用钛酸丁酯和氢氧化钠的水热反应制备了单斜相与锐钛矿相双晶相TiO2/多壁碳纳米管(简称MWNTs)复合材料,并考察了复合材料的可见光光催化活性。结果显示:MWNTs的加入可调控TiO2的晶相组成,增强TiO2的光催化活性,其中含5%MWNTs的样品具有较高的催化降解效率;随煅烧温度的升高,样品的光催化活性大幅提升。其机理归因于(1)促进单斜相和锐钛矿相双晶相结构的形成;(2)碳纳米管优良的导电作用及碳纳米管/TiO2间的异质结效应;(3)高温下碳纳米管分解产生的碳元素掺杂作用。     

Thermal hazard evaluation of carbon nanotubes with sulfuric acid by DSC

Many concerns over unsafe or unknown properties of multi-walled carbon nanotubes (MWNTs) have been raised. The thermal characteristics regarding stability would represent potential hazards during the production or utilization stage and could be determined by calorimetric tests for various thermokinetic parameters. Differential scanning calorimetry (DSC) was employed to evaluate the thermokinetic parameters for MWNTs at various compositions. Thermoanalytical curves showed that the average heat of decomposition (ΔH _d) of the MWNTs samples in a manufacturing process was about 31,723 J g⁻¹, by identifying them as an inherently hazardous material. In this study, significant thermal analysis appeared in the presence of sulfuric acid (H₂SO₄). From the DSC experiments, the purification process of MWNTs could induce an unexpected reaction in the condition of batch addition with reactants of H₂SO₄. The results can be applied for designing emergency relief system and emergency rescue strategies during a perturbed situation or accident.     

Property control of new forms of carbon materials by fluorination

Multiwall carbon nanotubes (MWNTs) based on the template carbonization technique were fluorinated in a temperature range 323-473 K by elemental fluorine. The fluorination of the carbon nanotubes results in functionalization and modification of pristine nanotubes with respect to adsorption and electrochemical properties. Selective fluorination of the inner surface of the carbon nanotubes, brings about a decrease in the surface free energy of the inner surface of the tubes and an increase in colombic efficiency of Li/nanotubes rechargeable cells in an aprotic medium. Electrochemical fluoride-ion doping of fullerene C₆₀ thin films (250-450 nm) was carried out in a fluoride-ion conductive solution, MeCN solution of 1 M Et₄NF·4HF. Galvanostatic oxidation yielded C₆₀F_ca.1-3 where fluorine exists as a semi-ionic species in the cavity surrounded by C₆₀ molecules without forming covalent CF bonds     

Prussian Blue electrodeposited on MWNTs-PANI hybrid composites for H2O2 detection

A Prussian Blue (PB)/polyaniline (PANI)/multi-walled carbon nanotubes (MWNTs) composite film was fabricated by step-by-step electrodeposition on glassy carbon electrode (GCE). The electrode prepared exhibits enhanced electrocatalytic behavior and good stability for detection of H₂O₂ at an applied potential of 0.0 V. The effects of MWNTs thickness, electrodeposition time of PANI and rotating rate on the current response of the composite modified electrode toward H₂O₂ were optimized to obtain the maximal sensitivity. A linear range from 8 × 10⁻⁹ to 5 × 10⁻⁶ M for H₂O₂ detection has been observed at the PB/PANI/MWNTs modified GCE with a correlation coefficient of 0.997. The detection limit is 5 × 10⁻⁹ M on signal-to-noise ratio of 3. To the best of our knowledge, this is the lowest detection limit for H₂O₂ detection. The electrode also shows high sensitivity (526.43 μA μM⁻¹ cm⁻²) for H₂O₂ detection which is more than three orders of magnitude higher than the reported.     

Magnetic assembled electrochemical platform using Fe2O3 filled carbon nanotubes and enzyme

A novel electrochemical nanostructured biosensor based on carbon nanotubes (CNTs) has been constructed by magnetic assembly method. The magnetic multi-walled carbon nanotubes (M-MWNTs) were prepared by introducing Fe₂O₃ nanoparticles into the nanotubes. Thus the multilayered functional platform could be assembled with the aid of magnetic field. The horseradish peroxidase (HRP) was employed as a model enzyme to demonstrate the final performance of the nanostructured biosensor. SEM, UV–vis spectroscopy and electrochemical techniques were used for characterization of assembly process. The resulting three-dimensional M-MWNTs/HRP multilayer films have showed satisfactory stability, biocompatibility and electrochemical properties.     

Synthesis and Characterization of Hyperbranched RuO2 Nanostructures

RuO₂ nanostructures were synthesized by heating Ru nanoparticles in air at 280°C using Cu as catalyst. The Ru nanoparticles were prepared by the pyrolysis of ruthenium precursors in a vacuum using multi-walled carbon nanotubes as templates. The RuO₂ nanostructures grew radically with diameters of 50–150 nm, and lengths of 0.5–2.0 μm. The growth of nanostructure mainly depends on the dispersivity of Ru nanoparticles on MWNTs. The electrochemical property of these nanostructures was studied by cyclic voltammetry. Electronic Supplementary Material Supplementary material for this article is available at and is accessible for authorized users.     

Amperometric Immunosensor Based on Gold Nanoparticles/Fe3O4-FCNTs-CS Composite Film Functionalized Interface for Carbofuran Detection

In this paper, a novel amperometric immunosensor for the determination of carbofuran based on gold nanoparticles (GNPs), magnetic Fe₃O₄ nanoparticles-functionalized multiwalled carbon nanotubes-chitosan (Fe₃O₄-FCNTs-CS), and bovine serum albumin (BSA) composite film was proposed. First, GNPs were immobilized onto the glassy carbon electrode (GCE) surface, and then the magnetic Fe₃O₄ nanoparticles mixed with chitosan-functionalized multiwall carbon nanotubes (CS-FCNTs) homogeneous composite (CS-FCNTs-Fe₃O₄) was immobilized onto the GNPs layer by electrostatic interactions between amino groups of CS and GNPs. Because chitosan (CS) contains many amino groups, it can absorb more antibodies. FCNTs have high surface area, high electrical conductivity, and it can enhance the electron transfer rate; Magnetite (Fe₃O₄) nanoparticles can provide a favorable microenvironment for biomolecules immobilization due to their good biocompatibility, strong superparamagnetic property, and low toxicity; and GNPs possess high surface-to-volume reaction, stability, and high conductivity. Gold Nanoparticles/Fe₃O₄-FCNTs-CS composite film was constructed onto the GCE surface, which had significant synergistic effects toward immunoreaction signal amplification. The stepwise assembly process was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), respectively. Under the optimal conditions, the current response was proportional to the concentration of carbofuran ranging from 1.0 ng/mL to 100.0 ng/mL and from 100.0 ng/mL to 200 µg/mL with the detection limit 0.032 ng/mL. The proposed immunosensor exhibited good accuracy, high sensitivity, and stability, and it can be used for detection of carbofuran pesticide.