Uniform directional alignment of single-walled carbon nanotubes in viscous polymer flow

In this work, we probed the effects of shear flow on the alignment of dispersed single-walled carbon nanotubes in polymer solutions. Two different systems were compared: Single-walled carbon nanotubes dispersed using an anionic surfactant and single-walled carbon nanotubes dispersed using an anionic surfactant and a weakly binding polymer. It was determined that the addition of the weakly binding polymer increased the degree of dispersion of the carbon nanotubes and the ability to induce their alignment when subjected to shear forces.     

碳纳米管在药物和基因转运领域的研究进展

当前,国内外的许多研究小组都致力于开发出新型有效的药物和基因转运系统,用于改善多种治疗因子的药理学作用并降低其毒性。在纳米材料这一类中,碳纳米管（Carbon Nanotubes, CNTs）正逐步引起人们的关注。功能化的CNTs的两个关键优势在于它具有很强的细胞穿透能力和较低的细胞毒性,使其在药物和基因转运领域中的应用成为可能。CNTs可通过形成稳定的共价键或形成以非共价键为基础的超分子结合物来运载肽类、蛋白质、核酸和药物等活性分子,并将其运送至特定的组织、器官中以表达特殊的生物学功能。针对这一研究热点,本文综述了近几年国内外关于碳纳米管在药物和基因转运领域中的应用进展,并探讨了其毒性,以期为这一领域中的研究工作者提供参考。     

Role of carbon nanotubes in electroanalytical chemistry: a review

This review covers recent advances in the development of new designs of electrochemical sensors and biosensors that make use of electrode surfaces modification with carbon nanotubes. Applications based on carbon nanotubes-driven electrocatalytic effects, and the construction and analytical usefulness of new hybrid materials with polymers or other nanomaterials will be treated. Moreover, electrochemical detection using carbon nanotubes-modified electrodes as detecting systems in separation techniques such as high performance liquid chromatography (HPLC) or capillary electrophoresis (CE) will be also considered. Finally, the preparation of electrochemical biosensors, including enzyme electrodes, immunosensors and DNA biosensors, in which carbon nanotubes play a significant role in their sensing performance will be separately considered.     

Self-organization of supramolecular microporous structures based on carbon nanotubes and benzene

The molecular dynamic has been used to study the self-organization of carbon nanotubes into an array in the presence of coordinating molecules. Methane adsorption on model systems has been calculated. It has been shown that secondary porosity formed by the nanotubes makes it possible to accumulate methane at the level of the best commercial adsorbents. Supramolecular systems have been synthesized on the basis of carbon nanotubes and benzene molecules used as coordinators according to a scheme realized in the numerical simulation. The specific adsorption of nitrogen at 293 K on the obtained supramolecular structure has been shown to increase by more than tenfold as compared with that on initial nanotubes.     

Graphite-incorporated MoS2 nanotubes: a new coaxial binary system

Graphite-filled MoS2 nanotubes were synthesized by pyrolizing propylene inside MoS2 nanotubes prepared by a template-assisted technique. The large coaxial nanotubes were constituted of graphite sheets inserted between the MoS2 layers, forming the outer part, and coaxial multiwall carbon nanotubes intercalated with MoS2 inside. High-resolution electron microscopy (HREM) and electron energy loss spectroscopy techniques along with molecular dynamics simulation and quantum mechanical calculations were used to characterize the samples. The one-dimensional structures exhibit diverse morphologies such as long straight and twisted nanotubes with several structural irregularities. The interplanar spacing between the MoS2 layers was found to increase from 6.3 to 7.4 A due to intercalation with carbon. Simulated HREM images revealed the presence of mechanical strains in the carbon-intercalated MoS2 layers as the reason for obtaining these twisted nanostructures. The mechanism of formation of carbon-intercalated MoS2 tubular structures and their stability and electronic properties are discussed. Our results open up the possibility of using MoS2 nanotubes as templates for the synthesis of new one-dimensional binary-phase systems.     

基于碳纳米管的超级电容器研究进展

综述了基于碳纳米管及其复合材料作超级电容器的电极材料的研究现状,通过对碳纳米管的改性或与其它材料复合,能有效地提高电容器的电容特性。总结了近几年来在开发超级电容器电极材料领域中对碳纳米管的活化和提高碳纳米管的分散性技术、碳纳米管与过渡金属氧化物复合材料、碳纳米管与导电聚合物复合材料以及碳纳米管与石墨烯复合材料研究的进展。     

碳纳米管在水中的分散性

以超声波为辅助工具,分别研究阳离子、阴离子型等表面活性剂在水中对碳纳米管分散性的影响,进而研究两种表面活性剂复配后对碳纳米管分散性的影响。通过记录分散的碳纳米管溶液的保存时间和SEM对分散效果进行分析和观察。     

Effects of surface heterogeneity of carbon nanotubes in adsorption of colloid nanoparticles studied by means of computer simulations

This work deals with a construction of an implicit solvent model which can be used in molecular dynamics simulations of systems comprising colloid nanoparticles and carbon nanotubes. Such systems, due to finite sizes of both components, cannot be accurately approximated by a smaller slab geometry and thus represent a particularly difficult case in terms of computer simulations. Adsorption of large colloid nanoparticles on the surfaces of carbon nanotubes were studied and we determined the adsorption energy profiles of the nanoparticles on the carbon nanotubes surfaces. We also determined the adsorption isotherms which help to understand a preferred location of the nanoparticles on the nanotubes surfaces.     

Present and future applications of carbon nanotubes to analytical science

This article reviews the impact of carbon nanotubes on analytical science, and the main current and future applications of carbon nanotubes in this field. Given that it is necessary to solubilize carbon nanotubes for many applications, we consider the procedures developed to achieve this. The use of carbon nanotubes in analytical chemistry as a target analyte and as an analytical tool is also discussed. Chromatographic and electrophoretic methods used to separate and characterize carbon nanotubes are presented. The use of carbon nanotubes as an analytical tool in filters and membranes, as sorbent material for solid phase extraction, in electrochemical (bio)sensors, and in separation methods is discussed. It is clear that while nanotubes are being tested for use in many different fields, their truly enormous potential has yet to be realized in analytical chemistry.Dedicated to the memory of Wilhelm Fresenius     

Carbon nanotubes as solid-phase extraction sorbents prior to atomic spectrometric determination of metal species: A review

New materials have significant impact on the development of new methods and instrumentation for chemical analysis. From the discovery of carbon nanotubes in 1991, single and multi-walled carbon nanotubes – due to their high adsorption and desorption capacities – have been employed as sorption substrates in solid-phase extraction for the preconcentration of metal species from diverse matrices. Looking for successive improvements in sensitivity and selectivity, in the past few years, carbon nanotubes have been utilized as sorbents for solid phase extraction in three different ways: like as-grown, oxidized and functionalized nanotubes. In the present paper, an overview of the recent trends in the use of carbon nanotubes for solid phase extraction of metal species in environmental, biological and food samples is presented. The determination procedures involved the adsorption of metals on the nanotube surface, their quantitative desorption and subsequent measurement by means of atomic spectrometric techniques such as flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry/mass spectrometry, among others. Synthesis, purification and types of carbon nanotubes, as well as the diverse chemical and physical strategies for their functionalization are described. Based on 140 references, the performance and general properties of the applications of solid phase extraction based on carbon nanotubes for metal species atomic spectrometric determination are discussed.     

A study of the stability of aqueous suspensions of functionalized carbon nanotubes

The properties of aqueous suspensions of carbon nanotubes have been studied as depending on the conditions of their functionalization in a mixture of sulfuric and nitric acids. The elemental composition and contents of carboxyl, lactone, and hydroxyl groups in carbon nanotubes have been determined at different durations and temperatures of functionalization. The influence of functionalization conditions on the value of the electrokinetic potential of carbon nanotubes in aqueous suspensions and the nanotube solubility in water has been investigated. It has been found that the absolute value of the electrokinetic potential of nanotubes and their solubility in water increase with both the duration and temperature of functionalization due to a rise in the number of functional groups on their surface. The optimal regimes of functionalization of carbon nanotubes have been determined from the point of view of preserving their structure and stability in aqueous dispersions.     

Progress and Challenges for the Bottom-Up Synthesis of Carbon Nanotubes with Discrete Chirality

Carbon nanotubes (CNTs) have emerged as some of the most promising materials for the technologies of the future. One of the most significant limitations to furthering the understanding and application of these fascinating systems is the lack of atomic-level structural control in their syntheses. Current synthetic methods produce mixtures of structures with varying physical properties. In this article, we describe the potential advantages, recent advances, and challenges that lie ahead for the bottom-up organic synthesis of homogeneous carbon nanotubes with well-defined structures.     

Aligned Nanotubes

Since the discovery of carbon nanotubes by Iijima in 1991, various carbon nanotubes with either a single‐ or multilayered graphene cylinder(s) have been produced, along with their noncarbon counterparts (for example, inorganic and polymer nanotubes). These nanostructured materials often possess size‐dependent properties and show new phenomena related to the nanosize confinement of the charge carriers inside, which leads to the possibility of developing new materials with useful properties and advanced devices with desirable features for a wide range of applications. In particular, carbon nanotubes have been shown to exhibit superior properties attractive for various potential applications, ranging from their use as novel electron emitters in flat‐panel displays to electrodes in electrochemical sensors. For many of the applications, it is highly desirable to have aligned/patterned forms of carbon nanotubes so that their structure/property can be easily assessed and so that they can be effectively incorporated into devices. In this Review, we present an overview on the development of aligned and micropatterned nanotubes, with an emphasis on carbon nanotubes.     

碳纳米管共价功能化

碳纳米管由于其独特的结构与优异的各项性能,在许多领域具有巨大的应用潜力,已引起了广泛的关注。由于碳纳米管不溶于水和有机溶剂,极大地制约了其性能应用,因此碳纳米管的功能化就成为目前研究的热点。本文侧重于碳纳米管的共价功能化,详细讨论了碳纳米管不同位置共价功能化的研究进展。     

新型碳纳米材料在低温燃料电池催化剂中的应用

 碳纳米管及其衍生纳米碳材料是一种介于富勒烯与石墨之间的碳的存在形式,具有独特的电子性质. 碳纳米材料可与其表面负载的金属活性相产生一种特殊的载体-金属相互作用; 纳米管中电子转移的动力学行为极佳,并且其特殊的纳米级孔道结构有利于反应物及产物的传质,因此作为低温燃料电池催化剂载体备受关注. 综述了多种新型碳纳米材料如碳纳米管、碳纳米纤维、碳纳米盘、碳纳米角和碳纳米分子筛等在低温燃料电池催化剂中的应用,并对其存在的问题和可能的发展方向进行了讨论.     

Pentagon-Embedded Cycloarylenes with Cylindrical Shapes

Cylinder-shaped graphitic networks in carbon nanotubes have attracted interest from scientists in various disciplines. The chemical synthesis of segments thereof is considered as a challenging and appealing subject in chemistry, and deepens our understanding of curved and conjugated arrays of hexagons. We herein report the synthesis of cylinder-shaped molecules containing non-hexagon bridges in their conjugated systems. Multiple pentagon units were embedded in the cylinder-shaped discrete molecules, and the stereoisomerism originating from their helical carbon arrangements was studied. Structural analysis by NMR, UV/Vis absorption spectroscopy, and single-crystal X-ray diffraction provided fundamental experimental information on the curved systems with conjugation across the pentagons. This study provides the first experimental guide for further explorations of anomalous non-hexagon arrays of graphitic carbon materials with cylindrical shapes.     

Weak polyelectrolyte control of carbon nanotube dispersion in water

The dispersion of nanotubes by pH-responsive polymers (i.e., weak polyelectrolytes) enables the macroscopic properties of aqueous suspensions to be tuned. Microstructural changes were achieved as a function of pH in aqueous suspensions containing single-walled carbon nanotubes and imaged by cryogenic-TEM. Clear evidence of pH-sensitive nanotube dispersion is shown. We expect that many useful properties of these nanotube-polymer systems could be sensitive to microstructure, making this technique important for aqueous processing of carbon nanotubes and macroscopic tailoring of solid polymer nanocomposite behavior.     

Making carbon nanotubes biocompatible and biodegradable

Carbon nanotubes are promising nanomaterials with great potential in the field of nanomedicine for both therapeutic and diagnostic applications. Different approaches have been developed to render this material biocompatible and to modulate any ensuing toxic effects. In the context of medical use, although chemically functionalised carbon nanotubes display reduced toxicity, they are still considered with scepticism due to their perceived non-biodegradability. Recently, it has been demonstrated that functionalised carbon nanotubes can be degraded by oxidative enzymes. This finding is offering a new perspective for the development of carbon nanotubes in medicine. This article highlights recent advances that can act as paradigm-shifts towards the design of biocompatible and biodegradable functionalised carbon nanotubes and allow their translation into the clinic.     

Chemically Modified Carbon Nanotubes for Use in Electroanalysis

The discovery of carbon nanotubes has had a profound impact on many areas of science and technology, not least that of electroanalysis. The properties and applications of carbon nanotubes themselves have been well reviewed in the literature and a number of reviews with an electrochemical emphasis have been published. However, the modification of carbon nanotubes has recently been the focus of much research, primarily to improve their solubility in various solvents. Yet modified carbon nanotube electrodes also allow the electrochemist to tailor the properties of the carbon nanotubes, or the electrode surface to impart desired properties such as enhanced sensing capabilities. In this review we attempt to comprehensively cover the different chemical and electrochemical modification strategies and research carried out using modified carbon nanotubes for electroanalytical and bioanalytical applications. Furthermore we also discuss the use of modified carbon nanotubes in electrocatalysis and biocatalysis from an analytical aspect, as well as seeking to dispel some of the myths surrounding the “electrocatalytic” properties of carbon nanotubes.     

Biomimetic assemblies of carbon nanostructures for photochemical energy conversion

This feature article summarizes our recent accomplishments in the field of carbon nanostructures, fullerenes and carbon nanotubes, as integrative components in multifunctional hybrid cells that bear large promise for applications as photochemical energy conversion systems.