Effect of the Linking Group on the Thermoelectric Properties of Poly(Schiff Base)s and Their Metallopolymers

As polymer-based thermoelectric (TE) materials possess attractive features such as light weight, flexibility, low toxicity and ease of processibility, an increasing number of conducting polymers and their composites with high TE performances have been developed in recent years. Up to date, however, the research focusing on the structure-performance relationship remains rare. In this paper, two series of poly(Schiff base)s with either C=C or C≡C linker and their metallopolymers were synthesized and doped with single-walled carbon nanotubes to evaluate how the linking groups affected the TE properties of the resulting composites. Apart from the effect exerted by the morphology, experimental results suggested that the linkers played a key role in determining the band gaps, preferred molecular conformation and extent of conjugation of the polymers, which became key factors that influenced the TE properties of the resulting materials. Additionally, upon coordination with transition metal ions, the TE properties could be tuned readily.     

Electrical Properties of Single Walled Carbon Nanotube Reinforced Polystyrene Composites

Composites of carbon nanotubes (CNT) in polymeric matrices have attracted considerable attention in the research communities due to their good electrical conductivity, high stiffness and high strength at relatively low CNT contents. Effective utilization of CNT in composites depends primarily on the ability to disperse them homogeneously throughout the polymer matrix, avoiding the formation of bundles due to van der Waals interactions existing between the nanotubes. In this work composites of polystyrene at various percentages of SWNT were fabricated using Latex Technology technique, a polymer type-independent method based on using a surfactant as a dispersing agent. An electrical characterization of SWNT composites was performed both in DC and AC modes. From the analysis of DC data a percolative behavior was found for the conductivity as function of SWNT content. The innovative contribution of this work consists in the modeling of the composite material upon its electrical properties. AC measurements and the analysis of impedance as function of angular frequency lead to the formulation of an equivalent circuit able to model the composite material in correspondence of the percolative threshold.     

碳纳米纸/聚乙烯复合材料的电热性能研究

为改善碳纳米管(CNT)分散性,将CNT先制备成碳纳米纸(CNP),然后将CNP与高密度聚乙烯(HDPE)进行复合压膜形成具有三明治结构的CNP/HDPE复合材料,详细研究了CNP的形貌、孔结构、力学性能以及CNP/HDPE复合材料的电热性能。结果表明:采用悬浮过滤法可获得表面平整、光滑、孔径均匀的碳纳米纸;碳纳米纸孔径大部分集中在20nm~40nm之间;碳纳米纸具有一定的强度和柔韧性。CNP/HDPE复合材料的拉伸强度和拉伸模量略高于纯HDPE;在碳纳米管含量相同时,在相同电压下,CNP/HDPE复合材料其电热性能远高于以共混方式制备的CNT/HDPE复合材料。     

Molecular Modeling Study of Drug-DNA Combined to Single Walled Carbon Nanotube

One of the applications of nanotechnology is use of carbon nanotubes for the targeted delivery of drug molecules. To demonstrate the physical and chemical properties of biomolecules and identify new material of drug properties, the interaction of carbon nanotubes (CNTs) with biomolecules is a subject of many investigations. CNTs is a synthetic compound with extraordinary mechanical, thermal, electrical, optical, and chemical properties widely applied for technological purposes. In this article we have tried to investigate thermodynamic parameters and dielectric effects in different solvents for one of the most famous anticancer drug ??cisplatin?? combined to SWCNT, by Monte Carlo and density functional theory (DFT) calculations. Cause of platinum element in cisplatin we have done calculations as Gibbs free energy, thermal enthalpy, thermal energy and entropy at 6-31G** basis set with SCRF model of solvent. In this work, the major point has been embedded that results of both two methods of Monte Carlo and DFT can overlap with each other and cisplatin- SWCNT is a suitable compound for drug delivery in different media.     

Engineered Molecular Chain Ordering in Single‐Walled Carbon Nanotubes/Polyaniline Composite Films for High‐Performance Organic Thermoelectric Materials

Single‐walled carbon nanotubes (SWNTs)/polyaniline (PANI) composite films with enhanced thermoelectric properties were prepared by combining in situ polymerization and solution processing. Conductive atomic force microscopy and X‐ray diffraction measurements confirmed that solution processing and strong π–π interactions between the PANI and SWNTs induced the PANI molecules to form a highly ordered structure. The improved degree of order of the PANI molecular arrangement increased the carrier mobility and thereby enhanced the electrical transport properties of PANI. The maximum in‐plane electrical conductivity and power factor of the SWNTs/PANI composite films reached 1.44×10³ S cm^?1 and 217 μW m^?1 K^?2, respectively, at room temperature. Furthermore, a thermoelectric generator fabricated with the SWNTs/PANI composite films showed good electric generation ability and stability. A high power density of 10.4 μW cm^?2 K^?1 was obtained, which is superior to most reported results obtained in organic thermoelectric modules.     

柔性热电器件的制备与性能研究

介绍了有机/无机复合热电材料的柔性器件, 按照柔性器件的组装制备方式, 以串联型、 堆砌型和折叠型3种类型, 详细地总结了其制备过程与器件热电性能, 探讨该领域的研究进展, 并对其发展前景进行展望.     

Preparation and Properties of Pyrene-Modified Multi- Walled Carbon Nanotube/Epoxy Resin Nanocomposites

Nanocomposites of multi-walled carbon nanotube (MWCNT)/bis-phenol A type epoxy resin were prepared and physical properties of the nanocomposites were investigated. For the fine dispersion of MWCNT in the epoxy resin, MWCNT was modified with pyrene butyric acid (PBA) in the supercritical carbon dioxide (CO₂). The physical adsorption of PBA on the surface of MWCNTs was studied with a thermogravimetric analyzer and a transmission electron microscopy. The electrical surface resistivities of the nanocomposites showed threshold decreases due to percolations above the critical concentration of the MWCNT. The resistivities showed maximum depending on the concentration and the modification of the surface of the MWCNT with PBA. It is postulated that the dispersion of the MWCNT in epoxy resins resulted in dispersion systems which exhibit rheological properties similar to lyotropic liquid crystalline polymers. The surface resistivities of the MWCNT/epoxy systems reflected the morphological characteristics of the systems which also determined rheological properties of the systems.     

Preparation of Amino-functionalized Multiwall Carbon Nanotube/Gold Nanoparticle Composites

Multiwall carbon nanotubes (MWNT) were modified orderly with carboxyl groups and amino groups. The MWNT/gold nanoparticle composites were formed when the amino‐functionalized MWNT was interacted with gold colloids. The functionalized MWNT was characterized using Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The amino‐functionalized MWNT allows further attaching gold nanoparticles through electrostatic interaction between the negatively charged gold nanoparticles and amino groups on the surface of the MWNT. The composite of gold nanoprticles and amino‐functionalized MWNT was characterized by transmission electron microscopy. This method decorating carbon nanotubes can be used to identify the location of functional groups, i.e. defect sites on carbon nanotubes.     

Synthesis of Multishell Carbon Nanotube Composites via Template Method

Multishell nanotubes of polyaniline and carbon were synthesized via a template approach. A thin layer of MnO₂ coated on carbon nanotubes acts as a reactive template for the consequent formation of the polyaniline coating. The polyaniline-carbon nanotubes show enhanced dispersibility in water and can be possibly used as a functional material of electrochemical capacitors with improved performance. The general method operates by coating carbon nanotubes on functional materials such as poly (3,4-ethylenedioxythiophene), polypyrrole, silica, and carbon.     

添加La的Bi2Te3和Bi0.5Sb1.5Te3热电材料的电磁感应熔炼法制备及其热电性能

在N2气保护下,采用电磁感应法制备了添加La的Bi2Te3和Bi0.5Sb1.5Te3。运用X射线粉末衍射、电感耦合等离子光谱和扫描电子显微镜对材料的物相成分和形貌进行了表征。研究了La对Bi2Te3和Bi0.5Sb1.5Te3热电材料的电导率(σ)、Seebeck系数(S)和热导率(κ)的影响。实验结果表明,添加La明显降低了2种材料的热导率,提高了热电优值(ZT),添加La的Bi0.5Sb1.5Te3的热电优值在室温超过了1。     

单壁碳纳米管-氨基二茂铁复合物修饰玻碳电极对对硝基苯酚的电化学检测

本研究用氨基二茂铁(Aminoferrocene,AFc)经重氮化反应后修饰单壁碳纳米管(SWNTs),制备SWNTs-AFc复合物,并以该复合物修饰玻碳电极(GCE),通过循环伏安法(CV)和差分脉冲伏安法(DPV)等电化学方法检测对硝基苯酚(p-NP)。结果表明,与裸玻碳电极相比,SWNTs-AFc/GCE对p-NP响应的还原过电位显著减小,峰电流大大增强,p-NP的检测线性范围为1~850μmol/L(R2=0.997),检测限为1μmol/L。该方法电流响应快、灵敏度高、检测限低,具有良好的应用前景。     

三维碳微米管/碳纳米管复合结构的制备及在超级电容器中的应用

利用天然生物质杨絮特殊的管状结构通过简单的高温碳化法制备出碳微米管(CMTs). 将所得到的碳微米管作为基底, 采用化学气相沉积法制备出三维结构的碳微米管/碳纳米管(CNTs)复合材料. 利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)光谱仪、拉曼光谱仪对其进行了详细分析. 通过两电极测试体系对其超级电容性能进行测试, 碳微米管/碳纳米管复合电极在1 mol·L^-1Li₂SO₄电解液中的比电容值可达77 F·g^-1, 远大于碳微米管的比电容值(23 F·g^-1).     

Achieving Direct Electrical Connection to Glucose Oxidase Using Aligned Single Walled Carbon Nanotube Arrays

Direct electron transfer between an electrode and the redox active centre of glucose oxidase, flavin adenine dinucleotide (FAD), is probed using carbon nanotube modified gold electrodes. Gold electrodes are first modified with a self‐assembled monolayer of cysteamine and then shortened single walled carbon nanotubes (SWNT) are aligned normal to the electrode surface by self‐assembly. The electrochemistry of these aligned nanotube electrode arrays is initially investigated using potassium ferricyanide which showed SWNT act as nanoelectrodes with the ends of the tubes more electrochemically active than the walls. Subsequently the nanotubes are plugged into the enzymes in one of two ways. In the first method, native glucose oxidase is covalently attached to the ends of the aligned tubes which allowed close approach to FAD and direct electron transfer to be observed with a rate constant of 0.3 s^?1. In the second strategy, FAD was attached to the ends of the tubes and the enzyme reconstituted around the surface immobilized FAD. This latter approach allowed more efficient electron transfer to the FAD with a rate constant of 9 s^?1.     

硫/多孔碳纳米管复合材料的制备及电化学性能

为了解决单质硫导电性差、充放电过程中体积膨胀、中间产物多硫化物的穿梭效应等问题,将硫负载于一种高比表面积的多孔碳纳米管（PCNTs）,制备了S/PCNT复合材料,研究了其电化学性能。相比于S/CNT,S/PCNT的电化学性能有明显提升,这可归因于S/PCNT中的嵌入结构,为硫在充放电过程中的体积膨胀提供了缓冲空间,避免了硫与电解液的直接接触,进而有效限制多硫化物的溶解,从而缓解多硫化物的穿梭效应,使硫正极具有更好的循环稳定性。     

碳纳米管-聚乙烯复合材料的介电性能

采用熔融共混及模压的方法制备了碳纳米管(CNT)-高密度聚乙烯(HDPE)复合材料,并用介电谱仪研究了逾渗值附近的导电填料对复合材料体系在不同温度、频率条件下的介电常数、介电损耗、交流电阻率的变化规律。结果表明:复合材料的介电常数、介电损耗均随CNT质量分数增加而逐渐增大;在频率为103~106 Hz,温度为40~130℃时,HDPE基体的介电常数随频率和温度的变化较小,而添加CNT填料的复合材料的介电常数随频率和温度的增加而略微降低。当w(CNT)0.5%时,复合材料的交流电阻率表现出对频率的强烈依赖性;而当w(CNT)0.5%时,在低频处表现出直流特性,在高频处显示出交流电阻率的降低。     

纳米二氧化钛/碳纳米管复合催化剂光催化性能及碳纳米管组分的作用

运用溶胶-凝胶及低温水热法合成纳米TiO₂/碳纳米管复合催化剂, 以甲基橙为目标降解物考察复合物的光催化活性. 运用X光衍射、透射电镜、Brunauer-Emmett-Teller低温氮气吸附、差热-热重分析及紫外-可见漫反射吸收光谱等表征催化剂. 结果表明, 与单纯纳米TiO₂相比, 溶胶-凝胶法制备的复合催化剂的光催化活性显著提高, 实验条件下复合的碳纳米管最适含量为3%(碳纳米管/TiO₂, 重量百分比), 复合催化剂经在缓和氧化气氛中焙烧处理可在保持碳纳米管热稳定前提下获得纳米TiO₂的充分晶化. 观察到了低温水热合成的复合催化剂的甲基橙降解活性的进一步提升, 复合催化剂中纳米TiO₂在碳纳米管表面分散均匀, TiO₂和碳纳米管组分间的紧密和充分键合及低温水热条件下催化剂的大比表面积、超细粒径以及碳纳米管的热稳定等有利于复合催化剂的光催化活性. 进一步地, 探讨了复合催化剂中适量碳纳米管组分的光活性促活机制.     

Effect of the Nanotube Radius and the Volume Fraction on the Mechanical Properties of Carbon Nanotube-Reinforced Aluminum Metal Matrix Composites

By using the advantages of carbon nanotubes (CNTs), such as their excellent mechanical properties and low density, CNT-reinforced metal matrix composites (MMCs) are expected to overcome the limitations of conventional metal materials, i.e., their high density and low ductility. To understand the behavior of composite materials, it is necessary to observe the behavior at the molecular level and to understand the effect of various factors, such as the radius and content of CNTs. Therefore, in this study, the effect of the CNT radius and content on the mechanical properties of CNT-Al composites was observed using a series of molecular dynamics simulations, particularly focusing on MMCs with a high CNT content and large CNT diameter. The mechanical properties, such as the strength and stiffness, were increased with an increasing CNT radius. As the CNT content increased, the strength and stiffness increased; however, the fracture strain was not affected. The behavior of double-walled carbon nanotubes (DWNTs) and single-walled carbon nanotubes (SWNTs) was compared through the decomposition of the stress–strain curve and observations of the atomic stress field. The fracture strain increased significantly for SWNT-Al as the tensile force was applied in the axial direction of the armchair CNTs. In the case of DWNTs, an early failure was initiated at the inner CNTs. In addition, the change in the elastic modulus according to the CNT content was predicted using the modified rule of mixture. This study is expected to be useful for the design and development of high-performance MMCs reinforced by CNTs.     

原位氮掺杂碳包覆CoxP复合物的制备及其锂电性能

以类沸石咪唑酯骨架化合物ZIF-67为钴源、碳源和氮源前驱体,红磷作为磷源,在800 ℃煅烧直接制备氮掺杂碳包覆的Co₂P@N-C和CoP@N-C复合物,并研究其作为锂离子电池负极材料的电化学性能。 结果表明,所得复合物的组分可以通过调控ZIF-67和红磷的比例而改变。 所得复合物的结构为正十二面体,尺寸约250~400 nm,具有良好的导电性。 用作锂离子电池电极材料时,在电流密度为0.05 A/g下,Co₂P@N-C和CoP@N-C复合物首次放电容量分别达到942和1170.6 mA·h/g。 在1 A/g的电流密度下,经过500次循环容量依然可以保持在306.6和180.3 mA·h/g。 论文提供了一种绿色环保制备锂电池用磷化钴/碳复合物的简易方法。     

Single‐Walled Carbon Nanotube/Metalloporphyrin Composites for the Chemiresistive Detection of Amines and Meat Spoilage

Chemiresistive detectors for amine vapors were made from single‐walled carbon nanotubes by noncovalent modification with cobalt meso‐arylporphyrin complexes. We show that through changes in the oxidation state of the metal, the electron‐withdrawing character of the porphyrinato ligand, and the counteranion, the magnitude of the chemiresistive response to ammonia could be improved. The devices exhibited sub‐ppm sensitivity and high selectivity toward amines as well as good stability to air, moisture, and time. The application of these chemiresistors in the detection of various biogenic amines (i.e. putrescine, cadaverine) and in the monitoring of spoilage in raw meat and fish samples (chicken, pork, salmon, cod) over several days was also demonstrated.     

碳纳米管/石墨烯复合结构及其电化学电容行为

本文综述了超级电容器电极材料碳纳米管/石墨烯复合结构的制备方法,以及由该结构和赝电容活性物质形成的三元复合体系的电化学电容行为研究进展,并提出合理设计的碳纳米管和石墨烯复合结构可以有效发挥其高电导率、高比表面积和合理孔隙结构的优势,实现活性物质的高密度负载,从而获得具有高容量、良好倍率特性和长寿命的电化学超级电容器电极材料。