Advanced technology for functionalization of carbon nanotubes

Functionalization of carbon nanotubes (CNTs) has attracted considerable interest in the fields of physics, chemistry, material science and biology. The functionalized CNTs exhibit improved properties enabling facile fabrication of novel nanomaterials and nanodevices. Most of the functionalization approaches developed at present could be categorized into the covalent attachment of functional groups and the non-covalent adsorption of various functional molecules onto the surface of CNTs. This review highlights recent development and our work in functionalization of carbon nanotubes, leading to bio-compatible CNTs, fluorescent CNTs and transition metal functionalized CNTs. These novel methods possess advantages such as simplified technical procedures and reduced cost of novel nanomaterials and nanodevices fabrication.     

碳纳米管改性的蜡基复合粘结剂

通过熔融共混将功能化的碳纳米管引入到蜡基粘结剂中,得到碳纳米管改性的复合粘结剂.扫描电镜(SEM)显微照片显示,功能化的碳纳米管能均匀分散在粘结剂基体中.偏光显微照片和热性能分析结果表明,碳纳米管的加入能有效地提高粘结剂的结晶度和热稳定性,进而改善生坯在脱脂时的保形性.碳纳米管与粘结剂的非共价键结合有助于碳纳米管的均匀分散,更可能有利于复合材料成型后的脱脂.     

Carbon nanotubes in biology and medicine: An overview

Rapid development in the field of nanomedicine is bringing novel opportunities for improved disease diagnosis and drug delivery. Among various nanomaterials involved in nanomedicine, carbon nanotubes (CNTs) possessing a unique one-dimensional structure with interesting intrinsic mechanical, physical, and chemical properties have been extensively explored for a wide range of applications in biology and medicine. This review article provides an overview of how CNTs are used in different aspects of biomedicine including drug delivery and cancer treatment, bio-sensing, biomedical imaging, as well as tissue engineering. The recent developments, future perspective, and major challenges in this field are discussed.     

选择性湿法刻蚀制备内嵌碳纳米管的沟槽结构

提出一种“自下而上”的纳米结构的制备方法。在生长有碳纳米管的氧化硅表面沉积数纳米的钯金属膜后, 用氢氟酸刻蚀, 得到完全由碳纳米管引导的沟槽结构, 并且碳纳米管沿沟槽分布在其底部。通过导电原子力显微镜对沟槽内的碳纳米管的表征, 发现其仍然具有良好的导电性。在碳纳米管和钯金属膜之间增加一层磁控溅射沉积的氧化硅, 可以增加沟槽的深宽比。通过降低钯金属膜的致密程度, 沟槽的开口宽度可降至100 nm左右。该方法制备的结构可以进一步用来构建基于碳纳米管的纳电子器件。     

碳纳米管表面电荷电分布及尖端电场研究

碳纳米管具有一些特殊的物理性质，其中潜藏着重要的技术价值。从理论上具体研究了金属型碳纳米管周围的电势分布、纳米管表面电荷分布及其尖端附近的电场强度等静电特性，结果显示长径比小的碳纳米管尖端处所集聚电荷密度的相对值大，而长径比大的碳纳米管尖端处所集聚电荷密度的绝对值大，并且碳纳米管的尖端电场强度有很大的加强。这对理论上进一步探索碳纳米管的场发射机制有积极意义。     

碳纳米管在碳纤维纸上的生长研究

采用酞菁铁(FePc)作为碳源和催化剂源,利用化学气相沉积(CVD)法在碳纤维纸(CFP)上生长碳纳米管(CNTs),从而制备了碳纳米管/碳纤维纸复合材料,并利用扫描电镜(SEM)测试、X射线衍射(XRD)测试、接触角测试、电导率测试和孔隙率测试等方法对其结构和性能进行了表征.结果表明,碳纳米管能在碳纤维纸表面生长;表面生长碳纳米管后,碳纤维纸的疏水性、孔隙率和电导率均有所提高.     

Application of Raman spectroscopy in carbon nanotube-based polymer composites

Raman spectroscopy has been widely used to identify the physical properties of carbon nanotubes (CNTs), and to assess their func-tionalization as well as orientation. Recently, Raman spectroscopy has become a powerful tool to characterize the interfacial properties between CNTs and polymer matrices. This review provides an overview of micro-Raman spectroscopy of CNTs and its application in studying CNT reinforced polymer composites. Based on the specific Raman band shifts relating to the mechanical deformation of CNTs, Raman scattering can be used to evaluate the interactions between the CNTs and the surrounding polymer in the composites, and to detect the phase transitions of the polymer, and investigate the local stress state as well as the Young’s modulus of the CNTs. Moreover, we also review the current progress of Raman spectroscopy in various CNT macroarchitectures (such as films, fibers as well as composite fibers). The microscale structural deformation of CNT macroarchitectures and strain transfer factors from macroscale architectures to microscale structures are inferred. Based on an in situ Raman-tensile test, we further predict the Young’s modulus of the CNT macroarchitectures and reveal the dominating factors affecting the mechanical performances of the CNT macroarchitectures     

三种缺陷碳纳米管储氢性能分子动力学模拟研究

采用分子动力学（MD）方法对3种含有缺陷的椅式（5，5）、椅式（6，6）和齿式（10，0）碳纳米管储氢能力进行了模拟研究，考查了缺陷大小、缺陷位置、碳纳米管直径和螺旋性以及温度对碳纳米管储氢性能的影响．模拟结果表明；碳纳米管在80K时的储氢能力明显高于298K时的储氢能力；在相同条件下，直径较大的碳纳米管储氢性能优于直径较小的；当碳纳米管上的缺陷孔较小时，碳纳米管在室温下即可达到较高的储氢量，且缺陷位于碳纳米管端部时的储氢量大于缺陷位于管壁时的储氢量，而碳纳米管的螺旋性对储氢量影响较小；当缺陷孔的尺寸变大时，碳纳米管的储氢量明显下降，与此同时，碳纳米管的螺旋性对碳纳米管储氢量的影响趋于明显，而缺陷所在位置对储氢量的影响则相应减弱．     

多壁碳纳米管表面修饰化学官能团的定量分析

碳纳米管因其独特的结构及物理化学性质,已迅速成为化学、物理学、生物学及材料科学的研究热点。尽管在碳纳米管的定性表征方面发展了 许多成熟的技术,对其表面功能化化学基团的定量分析却相对滞后,目前已公开报道的文献较少且大多局限于单壁碳纳米管的分析,对多壁碳纳米管这方面的系统研究还未见报道。本文首先合成了羧基化、 氨基化两种多壁碳纳米管及三取代的羧基化C60,对多壁碳纳米管表面修饰的羧基和氨基进行了定量分析。结果发现酸碱滴定法是较为准确的测定多壁碳纳米管表面羧基含量的方法,脱Fmoc基团方法则能够 简单准确地定量功能化碳纳米管表面氨基的含量。     

Determination of electron orbital magnetic moments in carbon nanotubes

The remarkable transport properties of carbon nanotubes (CNTs) are determined by their unusual electronic structure. The electronic states of a carbon nanotube form one-dimensional electron and hole sub-bands, which, in general, are separated by an energy gap. States near the energy gap are predicted to have an orbital magnetic moment, mu(orb), that is much larger than the Bohr magneton (the magnetic moment of an electron due to its spin). This large moment is due to the motion of electrons around the circumference of the nanotube, and is thought to play a role in the magnetic susceptibility of CNTs and the magnetoresistance observed in large multiwalled CNTs. But the coupling between magnetic field and the electronic states of individual nanotubes remains to be quantified experimentally. Here we report electrical measurements of relatively small diameter (2-5 nm) individual CNTs in the presence of an axial magnetic field. We observe field-induced energy shifts of electronic states and the associated changes in sub-band structure, which enable us to confirm quantitatively the predicted values for mu(orb).     

基板焙烧温度与合成时间对V型火焰法于不锈钢基板直接生长碳纳米管的影响

为了实现于锅炉中直接制备附着碳纳米管的各类构件,采用自主研发的V型火焰法,在不锈钢基板上直接快速生长碳纳米管。通过SEM、XRD谱和Raman光谱分析了基板预处理温度和合成时间对碳纳米管生长过程,并对不同条件下产物的形态、结晶度进行了分析;通过EDS分析了附着碳纳米管的基板元素含量变化。结果表明：通过调整基板的焙烧温度,能够控制基板上碳管的密度和质量,焙烧温度为500~600oC时产物的产量和质量最优;本实验条件下,铁是促进碳纳米管生长的活性位点;碳纳米管的生长经过碳的溶解、扩散和析出的过程,本实验条件下,2min后碳管开始生长,7min得到的碳管均匀覆盖于基板表面,管壁笔直,杂质少。可见,V型火焰法能够直接在经过焙烧的不锈钢板上生长碳管,且合成时间短,预处理过程简单,为批量生产附着碳纳米管构件提供了简单有效的途径。     

化学镀CuNiP-碳纳米管复合材料的制备与表征

用化学镀的方法在多壁碳纳米管表面沉积Cu—Ni—P合金,制备碳纳米管复合材料．并对制备出来的复合材料进行透射电子显微镜（TEM）和X-射线衍射（XRD）表征．通过XRD对已制备的化学镀合金分析．得出沉积铜为立方面心结构而镍是非晶态．TEM观察复合碳纳米管,发现在其表面沉积有分散均匀纳米级的金属颗粒,Cu-Ni-P合金呈球形．     

催化剂、基底对ECR-CVD法制备碳纳米管的影响

采用电子回旋共振微波等离子体化学气相沉积技术(ECR CVD),CH4和H2为气源,分别以Fe3O4,Co纳米粒子及Fe(NO)3溶胶为催化剂在多孔硅基底上制备了碳纳米管;在Si(111)和石英基底上以Fe3O4纳米粒子为催化剂实现了碳纳米管的生长·使用扫描电子显微镜(SEM)、透射电子显微镜(TEM)对样品的形貌、尺寸及结构进行表征·讨论了催化剂和基底对碳纳米管形貌、密度和取向性的影响·结果表明:催化剂影响碳纳米管的成核密度和生长速度,基底通过影响催化剂的特性和分布均匀性,对碳纳米管的形貌和生长模式产生重要影响,以Fe3O4为催化剂在多孔硅上实现了碳纳米管的最优定向生长·     

原位法制取碳纳米管/尼龙6复合材料

为改善尼龙 6 (PA6 )的力学性能 ,加入碳 nm管(CNTs)与之复合 ,制作 CNTs/ PA6复合材料 ,以提高基体PA6的力学性能 ,特别是抗拉强度。通过采用原位法复合CNTs与 PA6 ,获得了由 OC C化学键连接的、理想的CNTs/ PA6界面的、且 CNTs在基体 PA6中分散均匀的CNTs/ PA6复合材料 ,其抗拉强度有较大幅度的提高 ,同时还保持较高的冲击韧性和延伸率。经检测 ,CNTs/ PA6复合材料的断裂界面不象其它纤维增强 PA6复合材料那样在纤维 / PA6界面上 ,而是在 PA6包裹层与 PA6基体界面上。研究结果表明 ,采用原位复合法 ,CNTs能够对 PA6基体起到很好的增强作用     

悬臂碳纳米管纯弯问题的非局部弹性解

基于Eringen非局部弹性理论和圆柱壳半无矩理论,研究了悬臂碳纳米管的纯弯曲问题。计及小尺度效应的影响,给出了单臂碳纳米管的应力-应变关系,得到了内力场和位移场的理论解。研究结果表明,对半径较小的碳纳米管,尺度效应较为明显。随着碳纳米管的半径增大,尺度效应逐渐减小。当碳纳米管的半径大于或等于8 nm时,可以忽略尺度效应的影响。     

碳纳米管／Mo复合粉末的制备

[摘要]以仲钼酸铵为前驱物,采用溶胶一凝胶法和氢气还原工艺制备了碳纳米管／Mo复合粉末材料．采用扫描电子显微镜（SEM）和x射线衍射（XRD）分析了微观形貌和相态组成．结果表明：在750℃还原保温3h可制备出碳纳米管／Mo复合粉末,还原生成的Mo粉颗粒在碳纳米管周围聚集,使碳纳米管在Mo粉中均匀分散;高于800℃还原,碳纳米管与Mo反应生成M02C相;而低于750℃还原,则有MoO2相残存．     

碳纳米管增强硬质合金的制备及性能研究

为改善硬质合金中增强体碳纳米管（carbon nanotubes,CNTs）的团聚问题,采用化学镀Ni方法对CNTs进行表面改性,利用气压烧结工艺制备了WC-10Co-CNTs硬质合金和WC-10Co-CNTs/Ni硬质合金。对镀Ni前后CNTs的表面形貌、结构及成分进行了分析表征,并研究了CNTs和CNTs/Ni对硬质合金组织及性能的影响。结果表明,CNTs经化学镀改性处理后,表面包覆了致密的纳米Ni颗粒,团聚现象明显改善;在WC-10Co中添加CNTs或CNTs/Ni后可以有效地细化硬质合金的晶粒,降低孔隙率;和未添加的比较,添加质量分数0.1%的CNTs的硬质合金和添加质量分数0.1%的CNTs/Ni的硬质合金抗弯强度分别提高了17.5%和28.2%,热扩散系数分别提高了23.5%和42.8%。     

未修饰碳纳米管的细胞毒性机理及其影响因素

随着碳纳米管（carbon nanotubes,CNTs）制备技术的成熟和潜在应用的开发,CNTs的毒性也逐渐引起人们的重视.就未修饰CNTs而言,目前已有大量的文献报道了它们的细胞毒性的效果、机理、影响因素等.一种观点认为,CNTs通过影响细胞粘附、细胞周期或引起细胞内氧化应激水平的提高等手段,导致细胞发生凋亡,存活率下降.但也有一些研究发现,CNTs具有较高的生物安全性,没有显著的细胞毒性.存在对立的实验结果的主要原因是影响CNTs细胞毒性的因素很多.CNTs杂质的种类和含量、纯化方法不同,细胞培养环境的不同甚至生物终点检测方法的不同,都会影响对CNTs细胞毒性的判断.CNTs本身的性质,包括长度/直径、分散性等也都影响着CNTs的细胞毒性.为了更准确地评估CNTs的细胞毒性,建立标准样品,统一检测方法势在必行,即建立CNTs标准品和暴露剂量标准,发展适合CNTs的细胞毒性检测方法.归纳总结了以上各方面的研究成果,对今后的相关研究提出看法和建议.     

A review of the large-scale production of carbon nanotubes: The practice of nanoscale process engineering

Carbon nanotubes (CNTs) are nanomaterials that have attracted great research interest because of their unique properties and promising applications. The controllable synthesis of CNTs is a precondition for their broad application. In this review, we consider nanoscale process engineering and assess recent progress in the mass production of ultra-long, inexpensive CNTs with good alignment as well as tunability in wall number and diameter for fundamental and engineering science applications across multiple scales. Cutting-edge nanoscale process engineering research in the areas of physics, chemistry, materials, engineering, ecology, and social science will allow us to obtain high added value and multi-functional advanced CNTs. The synthesis of CNTs with controllable chirality, good-alignment, and predetermined sizes and lengths still presents great challenges. Through multidisciplinary scientific research, advanced CNT-based materials will promote the development of a sustainable society.     

新型明胶基碳纳米管骨架活性炭的制备

催化裂解法制备的碳纳米管(CNTs)经混酸纯化后,均匀分散到明胶的溶液中,用乙醇析出得到明胶/碳纳米管海绵前驱体,再通过炭化、氢氧化钾活化处理制备出明胶基碳纳米管骨架活性炭.采用扫描电子显微镜(SEM)和透射电子显微镜(TEM)对样品的表面形貌进行表征,结果显示:碳纳米管能够很好地被明胶包覆,并均匀分散在整个基体中.比表面和孔结构测试结果表明:随着碳纳米管含量的增大,活性炭样品比表面积和总孔容先增大后减小.此外,还对明胶基碳纳米管骨架活性炭孔结构的形成机理进行了分析讨论.