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The use of carbon nanotubes in materials applications has been slowed due to nanotube insolubility and their incompatibility with polymers. We recently developed two protocols to overcome the insoluble nature of carbon nanotubes by affixing large amounts of addends to the nanotube sidewalls. Both processes involve reactions with aryl diazonium species. First, solvent-free functionalization techniques remove the need for any solvent during the functionalization step. This delivers functionalized carbon nanotubes with increased solubility in organic solvents and processibility in polymeric blends. Additionally, the solvent-free functionalization process can be done on large scales, thereby paving the way for use in bulk applications such as in structural materials development. The second methodology involves the functionalization of carbon nanotubes that are first dispersed as individual tubes in surfactants within aqueous media. The functionalization then ensues to afford heavily functionalized nanotubes that do not re-rope. They remain as individuals in organic solvents giving enormous increases in solubility. This protocol yields the highest degree of functionalization we have obtained thus far-up to one in nine carbon atoms on the nanotube has an organic addend. The proper characterization and solubility determinations on nanotubes are critical; therefore, this topic is discussed in detail. 相似文献
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单壁碳纳米管(SWNTs)由于具有独特的物理、化学性质,激起人们极大的研究兴趣。目前生产的SWNTs通常包含等量左旋和右旋对映异构体,无光学活性,极大地限制碳纳米管在光学和光电子领域的研究和应用。已报道的非共价法分离光学活性碳纳米管的方法主要有离子交换色谱法、nanotweezers选择法、密度梯度超高速离心法、共轭聚合物缠绕法和小分子吸附法。本文较为详尽地综述了非共价法分离光学活性碳纳米管的研究进展,对各种分离方法的机理进行阐述,并在此基础上分析这些方法和分离效果的关系,指导设计和合成新型的分离试剂。最后,本文还针对上述研究中存在的问题,提出了旋光性SWNTs分离技术的研究方向。 相似文献
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Poly(ethylene terephthalate) (PET) based nanocomposites have been prepared with single walled carbon nanotubes (SWNTs) through an ultrasound assisted dissolution-evaporation method. Differential scanning calorimetry studies showed that SWNTs nucleate crystallization in PET at weight fractions as low as 0.3%, as the nanocomposite melt crystallized during cooling at temperature 24 °C higher than neat PET of identical molecular weight. Isothermal crystallization studies also revealed that SWNTs significantly accelerate the crystallization process. Mechanical properties of the PET-SWNT nanocomposites improved as compared to neat PET indicating the effective reinforcement provided by nanotubes in the polymer matrix. Electrical conductivity measurements on the nanocomposite films showed that SWNTs at concentrations exceeding 1 wt% in the PET matrix result in electrical percolation. Comparison of crystallization, conductivity and transmission electron microscopy studies revealed that ultrasound assisted dissolution-evaporation method enables more effective dispersion of SWNTs in the PET matrix as compared to the melt compounding method. 相似文献
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Chui-Peng Kong Xin Gao Ran Jia Hong-Xing Zhang 《Journal of computational chemistry》2019,40(10):1073-1083
The nonbonded and bonded force field parameters for carbon atoms in single-wall carbon nanotubes (SWNT) are fitted by means of quantum chemistry calculations with considering the periodic boundary conditions. The nonbonded parameters between carbon atoms and hydrogen atoms are fitted as well. All the fitted parameters are verified by comparing to quantum chemistry results and by calculating Young's modulus. Adsorption of Hydrogen molecules are then carried out on a bundle of self-assembled SWNTs. The adsorption isotherms are consistent to the Freundlich equation. Both hydrogen molecules adsorbed outside and inside the SWNTs are counted. According to our result, hydrogen molecules adsorbed inside the SWNTs are more stable at a relatively high temperature and are playing an important part in total amount of the adsorbed molecules. While C(10,10) have the highest adsorption capacities in most of the temperatures, hydrogen molecules inside C(5,5) are the most stable of all the four kinds of SWNTs. Thus, balancing adsorption capacities and strength of interaction can be important in choosing SWNT for gas adsorption. Besides, we deduct an equation that can describe the relation between hydrogen pressure and amount of SWNTs based on our simulation results. The hydrogen pressure may decrease by adding SWNTs in the system. The fitting method in our system is valid to SWNTs and can be tested in further studies of similar systems. © 2018 Wiley Periodicals, Inc. 相似文献
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Xiao Li Kun‐Feng Zhou Zhi‐Bo Tong Xi‐Ya Yang Cui‐Ying Chen Xue‐Hui Shang Jing‐Quan Sha 《化学:亚洲杂志》2019,14(19):3424-3430
To increase the conductivity of polyoxometalate‐based metal–organic frameworks (POMOFs) and promote their applications in the field of energy storage, herein, a simple approach was employed to improve their overall electrochemical performances by introducing a functionalized single‐walled carbon nanotubes (SWNT‐COOH). A new POMOF compound, [Cu18(trz)12Cl3(H2O)2][PW12O40] (CuPW), was successfully synthesized, then the size‐matched functionalized SWNT–COOH was introduced to fabricate CuPW/SWNT–COOH composite (PMNT–COOH) by employing a simple sonication‐driven periodic functionalization strategy. When the PMNT–COOH nanocomposite was used as the anode material for Lithium‐ion batteries (LIBs), PMNT–COOH( 3 ) (CuPWNC:SWNT‐COOH=3:1) showed superior behavior of energy storage, a high reversible capacity of 885 mA h g?1 up to a cycle life of 170 cycles. The electrochemical results indicate that the uniform packing of SWNT–COOH provided a favored contact between the electrolyte and the electrode, resulting in enhanced specific capacity during lithium insertion/extraction process. This fabrication of PMNT–COOH nanocomposite opens new avenues for the design and synthesis of new generation electrode materials for LIBs. 相似文献
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将单壁碳纳米管(SWNTs)和十二醛(DA)混合超声分散,得到均匀、稳定的无机-有机纳米复合材料(SWNTs-DA)。将其滴涂在玻碳电极表面晾干得到复合材料修饰电极(SWNTs-DA/GCE),再通过胺醛缩合反应将末端修饰氨基的单链DNA探针共价固定在SWNTs-DA/GCE表面,构建了一种新型的DNA电化学传感器。以[Fe(CN)6]3-/4-为电活性探针,采用循环伏安法和电化学阻抗法对传感器的层层组装过程进行表征。以亚甲基蓝(MB)作为杂交指示剂,考察了传感器分析性能。实验结果表明,MB在传感器上的峰电流值(Ip)与互补序列浓度对数值(lgcS2)在1.0×10-15~1.0×10-10mol/L范围内呈良好的线性关系(r=0.998)。根据3倍信噪比(S/N=3),计算得检出限为2.0×10-16mol/L。选择性实验表明该传感器能对互补序列、三碱基错配序列和非互补序列进行很好的识别。 相似文献
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《Analytical letters》2012,45(15):2432-2439
A new, highly selective, and sensitive technique has been developed for the detection of Hg2+ using singled-wall carbon nanotubes (SWNTs) and two kinds of oligonucleotides. The fluorescence of the thymine-rich single stranded DNA labeled with dye (the probe ssDNA) was effectively quenched by the SWNTs. In the presence of a target DNA (rich T-T mismatched with probe), the tightness of the DNA wrapping around the SWNTs was loosened. Since binding of Hg2+ turned the T-T mismatches to stable T-Hg2+-T base pairs, and the binding rate of DNA and the nanotube was lower than that of DNA hybridization, it induced the release of DNA molecules from the SWNTs, and this resulted in a remarkable increase of fluorescence compared to that of the DNA-SWNTs. The assay exhibited a dynamic response range for Hg2+ from 4.52 × 10?8 M to 7.21 × 10?7 M with a detection limit of 10 nM. 相似文献