功能化的多壁碳纳米管负载Pd电催化剂对甲酸的电催化氧化

以磺酸化的聚合物对多壁碳纳米管进行功能化，并以此为载体，采用室温下硼氢化钠还原法制备得到负载的Pd电催化剂，循环伏安（CV）和计时电流方法表明：功能化的碳纳米管为载体的Pd／MWCNTs催化剂对甲酸的电化学氧化具有较好的催化活性。     

Fabrication of multi-walled carbon nanotube reinforced polyelectrolyte hollow nanofibers by electrospinning

Hybrid hollow multi-walled carbon nanotubes (MWCNTs)/polyelectrolytes (PE) nanofibers were prepared by a combination of the electrospinning method and layer-by-layer (LbL) technique. The mixed polystyrene (PS)/MWCNTs nanofibers were obtained by electrospinning method, which were employed as templates to self-assembly multilayered polyelectrolytes by LbL technique. Hollow MWCNTs/PE nanofibers were obtained by selectively removed part of the template: PS, which is confirmed by Raman spectra, transmission electron microscopy (TEM) and scanning electron microscopy (SEM).     

Functionalization of multi-walled carbon nanotubes by radiation-induced graft polymerization in aqueous solution

A facile strategy for the preparation of water-soluble multi-walled carbon nanotubes (MWCNTs) in aqueous solution is proposed, where MWCNTs were treated by the concentrated mix acid and then functionalized by simultaneous radiation-induced graft polymerization of acrylic acid under the γ-ray. The structure of the grafted MWCNTs (denoted as MWCNT-g-PAAc) is characterized by means of FT-IR, ^lH NMR, Raman spectroscopies, TGA analysis, and TEM imaging. The degree of grafting was dependent on the reaction conditions such as the monomer concentration and the inhibitor concentration. The stability of the aqueous solution of MWCNT-g-PAAc is highly improved, where the solution is stable for more than 30 days at the concentration 1.5 g/L.     

Efficient direct water dispersion of multi-walled carbon nanotubes by functionalization with lysine

A small molecule, lysine, has been attached onto the Multi-Walled carbon nanotubes (MWNTs) by producing acyl chloride on the carboxylic groups associated with the nanotubes. Subsequently, highly water-dispersed nanotubes were obtained. Stable concentration as high as 10 mg/ml was obtained in deionized water that was nearly 2 orders of magnitude higher than that obtained from the acidized MWNTs. The functionalized MWNTs can be dispersed in water under a wide range of pH values (5-14) and exhibit pH responsive. Combining the properties of carbon nanotubes and the versatility and biocompatibility of lysine, these lysine functionalized MWNTs could find potential applications in biological applications. And this method could also be used to functionalize other nanomaterials by lysine.     

Control of neuronal network organization by chemical surface functionalization of multi-walled carbon nanotube arrays

Carbon nanotube substrates are promising candidates for biological applications and devices. Interfacing of these carbon nanotubes with neurons can be controlled by chemical modifications. In this study, we investigated how chemical surface functionalization of multi-walled carbon nanotube arrays (MWNT-A) influences neuronal adhesion and network organization. Functionalization of MWNT-A dramatically modifies the length of neurite fascicles, cluster inter-connection success rate, and the percentage of neurites that escape from the clusters. We propose that chemical functionalization represents a method of choice for developing applications in which neuronal patterning on MWNT-A substrates is required.     

Efficient surface functionalization of vertically-aligned carbon nanotube arrays using an atmospheric pressure plasma jet system

We demonstrate the facile and efficient surface functionalization of vertically-aligned carbon nanotube (VCNT) arrays using an atmospheric pressure plasma jet (APPJ) system. The VCNT arrays were synthesized on Fe-deposited SiO₂ wafers using an acetylene carbon source by thermal chemical vapor deposition method. To functionalize the surface of the VCNT arrays, the APPJ system was ignited using nitrogen gas at high voltage of 15 kV and frequency of 25 kHz. We varied the treatment time of the APPJ and the inter-distance between plasma jet and top surface of the VCNT in order to systematically investigate the optimal conditions of the APPJ system. The hydrophobic nature of the as-grown VCNT arrays was drastically changed to hydrophilic character via the facile APPJ treatment. X-ray photoelectron spectroscopy confirmed the formation of hydrophilic functional groups such as hydroxyl and carboxyl groups, and nitrogen-doping-related functionalities such as amines, in addition to pyrrolic- and pyridinic-bonding. The results prove that the APPJ treatment is a facile and efficient method for the surface modification of nanomaterials.     

Tetra-substituted cobalt (II) phthalocyanine/multi-walled carbon nanotubes as new efficient catalyst for the selective oxidation of styrene using tert-butyl hydroperoxide

Abstract

A novel tert-butyl hydroperoxide tetrasubstituted cobalt phthalocyanine (CoPc(OC₁₀H₁₄N)₄) was synthesized by the classical phthalonitrile method. Subsequently, the cobalt phthalocyanine (CoPc) was immobilized on the multi-walled carbon nanotubes (MWCNTs) by ultrasonic impregnation method to obtain CoPc(OC₁₀H₁₄N)₄/MWCNTs composites. The obtained composites were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM) and diffuse reflectance spectra (DRS) techniques. Using tert-butyl hydroperoxide (TBHP) as an environmentally friendly oxidant, CoPc(OC₁₀H₁₄N)₄/MWCNTs composites can be used as effective catalysts for the epoxidation of styrene. The effects of various variables, such as the mass ratio of CoPc(OC₁₀H₁₄N)₄/MWCNTs, reaction time, temperature, molar ratio of substrate/oxidant and the amount of catalyst on the catalytic capability were evaluated. The conversion of styrene reached 97.15%, and the epoxidation product achieved the selectivity of 84.44% under the optimal reaction conditions.     

多壁碳纳米管改性铂型IPMC的试验研究

将一种全氟磺酸树脂(Nafion)与多壁碳纳米管(MWCNTs)分别按质量比100:1、 100:3、 100:5进行配比, 采用溶剂浇铸法配合超声波分散法制备MWCNTs/Nafion型离子交换膜(IEM), 在此基础上利用化学沉积法制备铂型离子聚合物金属复合材料(Pt-IPMC), 考察三种MWCNTs负载量对IEM及Pt-IPMC性能的影响。采用SEM配合EDAX研究Pt的沉积效果, 对IEM及Pt-IPMC试样进行拉伸测试, 采用数字信号发生器为激励源测试Pt-IPMC的动态位移。结果表明: 添加MWCNTs使Pt-IPMC的内、 外电极厚度分别增加200%~250%和180%~200%, 使IEM及Pt-IPMC的弹性模量分别提高57.92%~140.85%和9.06%~52.85%; MWCNTs有效修饰了Pt-IPMC的内电极, 并明显提升其动态位移量、 动态响应及变形速度。     

载铜多壁碳纳米管的抗菌活性研究

采用溶胶-凝胶法在多壁碳纳米管(MWCNTs)表面负载纳米铜,制备复合抗菌材料MWCNTsCu。X射线能量色散谱(EDS)、透射电子显微镜(TEM)表征结果表明,纳米铜成功地负载在MWCNTs表面,纳米铜分散良好。以大肠杆菌为目标,评价了MWCNTs-Cu对水中细菌的抗菌活性,探讨了其抗菌机理。研究结果表明,MWCNTs-Cu对大肠杆菌表现出很强的抗菌性,其中,MWCNTs对大肠杆菌有强吸附性,纳米铜起主要杀菌作用。     

Thermo-oxidative decomposition of multi-walled carbon nanotubes: Kinetics and thermodynamics

Abstract

Multi-walled carbon nanotubes (MWCNTs) are familiar well owing to their capability of finding wide-reaching applications based on their fascinating properties. Kinetics of thermally activated processes in MWCNTs can help in understanding and controlling those processes which might eventually lead to develop materials with optimized efficiencies. Even though, inadequate information on the kinetics of thermal decomposition of WMCNTs has been reported in the literature, and its thermodynamics is yet to be addressed. In this regard, the present study deals with a detailed kinetic investigation on the thermo-oxidative decomposition of MWCNTs by employing advanced kinetic approaches. Kinetic analysis of MWCNTs decomposition reveals that although the kinetic triplets remain comparable, reaction model under isothermal condition is not the same as under non-isothermal conditions. It alters from contracting cylinder (non-isothermal) to random nucleation followed by isotropic growth of particles (isothermal). Thermodynamics of MWCNTs thermal decomposition points out that the process is non-spontaneous with enhanced endothermicity. In addition, the structure of activated complex is found to be relatively more organized in comparison with the reactant. An account of the interpretations of the obtained kinetic and thermodynamic parameters is also given and discussed in this study.     

管径相关的多壁碳纳米管膜的压阻效应

利用三点弯曲法研究了不同管径的碳纳米管膜的压阻效应,实验结果表明,管径较小的碳纳米管膜与管径大的碳纳米管膜相比具有更显著的压阻效应,并对电阻随应力变化的机制作了详细的讨论.     

Near-superhydrophobic behavior of multi-walled carbon nanotube thin films

Thin films of multi-walled carbon nanotubes created by standard drop and dry methodology are reported here to give water contact angles of ~ 138° accessing an intermediate region between smooth, apolar materials and superhydrophobic surfaces. Their near-superhydrophobic nature is attributed to hierarchical nanoscale roughness leading to the formation of Cassie-Baxter interfaces. While complete quantitative determination of surface energy parameters was prevented due to the porous nature of the films, the dispersive component of nanotube surface energy was found to be in the range of 39.1-47.8 mJ/m².     

Synthesis of multi-walled carbon nanotube/silver nanocomposite powders by chemical reduction in aqueous solution

Carbon nanotube (CNT)/silver nanocomposite powders with different volume fractions of CNTs 2.5, 5 and 10?vol.% were prepared by chemical reduction in solution. Multi-walled CNTs underwent surface modifications for functionalisations by acid treatments. The acid-treated CNTs were investigated by FT-IR and X-ray photoelectron spectroscopy. The spectroscopic investigations of the acid-functionalised CNTs detected that several kinds of functional groups attached with the graphene structure as well as produced short and de-caped CNTs. Acidic stannous chloride solution was used to sensitise the surface of the functionalised CNTs. Silver was deposited on the surface of sensitised CNTs with chemical reduction reaction of alkaline silver nitrate solution by formaldehyde at room temperature and pH?～?9. The morphology of the produced CNT/silver nanocomposite powder was investigated by high-resolution SEM and TEM. It was observed that the produced CNT/silver nanocomposite powders have decorated type of spherical silver particle size 2–5?nm deposited on the surface of CNTs as well as the CNTs were implanted in large spherical silver nanoparticles of particle size ～200?nm. The chemical analysis of the produced powder indicates that some oxygen content is included in the prepared powders which can be reduced by heat treatment at temperatures between 300°C and 400°C under hydrogen atmosphere.     

多壁碳纳米管的表面功能化及分散性研究

多壁碳纳米管(MWCNTs)分别经混合、强酸氧化浸泡和酰氯化处理后,再与9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)的衍生物(DHDOPO)进行接枝反应得到表面功能化的MWCNTs。利用傅里叶变换红外光谱仪(FT-IR)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、热重分析仪(TGA)、紫外-可见分光光度仪(UV-Vis)和沉降实验等分别表征改性前后MWCNTs的结构和表面形态,估算DHDOPO在MWCNTs表面的相对接枝率,研究改性前后MWCNTs在乙醇中的分散性。结果表明,MWCNTs经混合强酸氧化后表面出现羧基;DHDOPO在MWCNTs上的相对接枝率为51%;混合强酸氧化和表面接枝DHDOPO的MWCNTs在无水乙醇中具有良好的分散性。     

Noncovalent functionalization of multi-walled carbon nanotubes with siloxane polyether copolymer

Siloxane polyether copolymer (PSPEO), a new amphiphilic macromolecule, which consists of hydrophobic –Si–O–Si– main chain and hydrophilic pendant parts of polyethylene oxide (PEO), has a comb-polymer molecular structure and exhibits excellent properties such as super-wettability and extremely low surface tension. Multi-walled carbon nanotubes (MWNTs) can be easily solubilized in water by noncovalent functionalization with PSPEO. TEM, HRTEM and Raman spectra were used to characterize the functionalized MWNTs. The results reveal that PSPEO is adsorbed on surface of MWNTs, creating a 5–10 nm adsorption layer to impede the aggregation of nanotubes. TEM measurement confirmed the single-tube nature of the MWNTs suspensions. The MWNTs/PSPEO suspensions were stable over 3 months.     

Stress-strain behavior of multi-walled carbon nanotube/PEEK composites

This study examined the effects of multi-walled carbon nanotube (CNT) dispersion on stress-strain behaviors of poly-ether-ether-ketone (PEEK) at room temperature. Tensile test specimens containing 9 wt.% and 15 wt.% of CNT were fabricated using injection molding. Results of focused ion beam (FIB) observations show that many CNTs in the CNT/PEEK composite are aligned longitudinally. Although the PEEK stress-strain behavior is almost linear up to 1.5% strain, the stress-strain curves of CNT/PEEK composites exhibit considerable nonlinear and hysteretic behaviors from extremely low strain (<0.1%) under both tensile and compressive loading. The experimental results suggest that the viscoelastic deformation effects on nonlinear and hysteresis behaviors are not strong below 1.5% strain. Presumably, the slippage at the CNT-PEEK interface occurs with increasing applied stress because of poor interfacial load-transfer capability.     

Mechanical properties of multi-walled carbon nanotube/epoxy composites

Untreated and acid-treated multi-walled carbon nanotubes (MWNT) were used to fabricate MWNT/epoxy composite samples by sonication technique. The effect of MWNT addition and their surface modification on the mechanical properties were investigated. Modified Halpin–Tasi equation was used to evaluate the Young’s modulus and tensile strength of the MWNT/epoxy composite samples by the incorporation of an orientation as well as an exponential shape factor in the equation. There was a good correlation between the experimentally obtained Young’s modulus and tensile strength values and the modified Halpin–Tsai theory. The fracture surfaces of MWNT/epoxy composite samples were analyzed by scanning electron microscope.     

功能化碳纳米管的制备及功能化碳纳米管/尼龙6复合纤维

采用多聚磷酸(PPA)/P₂O₅弱酸体系, 通过傅克反应(Friedel-Crafts reaction)对多壁碳纳米管(MWCNTs)进行功能化改性, 加入己内酰胺后采用原位聚合法制备功能化碳纳米管(F-MWCNTs)/尼龙6(PA6)复合材料, 并熔融纺丝制备复合纤维。通过TEM、TG、DSC、SEM及力学性能测试对复合纤维进行表征。结果表明: 在MWCNTs表面成功地接枝了氨基, F-MWCNTs均匀地分散在PA6基体中, 没有发生团聚现象, 并且与基体具有很好的界面作用; F-MWCNTs的加入, 对复合纤维的熔融温度和结晶度影响不大, 结晶温度有所提高, 并明显提高了复合纤维的热稳定性; 随着F-MWCNTs的加入, 复合纤维的拉伸断裂强度和杨氏模量增加, 当F-MWCNTs质量分数为0.5%时, 拉伸断裂强度和杨氏模量达到最大, 比纯PA6纤维分别提高了45%和208%。     

1.6-己二胺化学修饰多壁碳纳米管

为获得两端具有活性端胺基的碳纳米管,通过化学方法对多壁碳纳米管(MWCNTs)接枝改性,利用氯化亚砜将MWCNTs酸处理产生的羧基转化为酰氯,进一步与1.6-己二胺发生亲核取代反应,将1.6-己二胺接枝到碳纳米管端部.采用X射线光电子能谱(XPS)、透射电镜(TEM)及扫描电镜(SEM)对化学修饰过程中各反应产物进行表征.结果表明:酸的切割作用,使碳纳米管从端帽下及管壁缺陷处打开,碳管长度由十几微米变为500nm左右;1.6-己二胺成功地接枝到碳纳米管端部,能谱分析(EDS)结果表明N元素接枝率达3.29%,接枝后的碳纳米管可以均匀分散在丙酮溶液中,并含有活性端胺基.     

Surface coating of multi-walled carbon nanotube nanopaper on shape-memory polymer for multifunctionalization

We are presenting a method of synthesizing three-dimensional self-assembled multi-walled carbon nanotube (MWCNT) nanopaper on hydrophilic polycarbonate membrane. The process is based on the very well-defined dispersion of nanotube and controlled pressure vacuum deposition procedure. The morphology and structure of the nanopaper are characterized with scanning electronic microscopy (SEM) over a wide range of scale sizes. A continuous and compact network observed from the microscopic images indicates that the MWCNT nanopaper could have highly conductive property. As a consequence, the sensing properties of conductive MWCNT nanopaper are characterized by functions of temperature and water content. Meanwhile, in combination with shape-memory polymer (SMP), the conductive MWCNT nanopaper facilitates the actuation in SMP nanocomposite induced by electrically resistive heating. Furthermore, the actuating capability of SMP nanocomposite is utilized to drive up a 5-gram mass from 0 to 30 mm in height.