Toxicity of Multi-Walled Carbon Nanotubes,Graphene Oxide,and Reduced Graphene Oxide to Zebrafish Embryos

Objective This study was aimed to investigate the toxic effects of 3 nanomaterials, i.e. multi-walled carbon nanotubes （MWCNTs）, graphene oxide （GO）, and reduced graphene oxide （RGO）, on zebrafish embryos. Methods The 2-h post-fertilization （hpf） zebrafish embryos were exposed to MWCNTs, GO, and RGO at different concentrations （1, 5, 10, 50, 100 mg/L） for 96 h. Afterwards, the effects of the 3 nanomateria on spontaneous movement, heart rate, hatching rate, length of larvae, mortality, and malformations Is were evaluated. Results Statistical analysis indicated that RGO significantly inhibited the hatching of zebrafish embryos. Furthermore, RGO and MWCNTs decreased the length of the hatched larvae at 96 hpf. No obvious morphological malformation or mortality was observed in the zebrafish embryos after exposure to the three nanomaterials. Conclusion MWCNTs, GO, and RGO were all toxic to zebrafish embryos to influence embryos hatching and larvae length. Although no obvious morphological malformation and mortality were observed in exposed zebrafish embryos, further studies on the toxicity of the three nanomaterials are still needed.

Enhanced cycle performance of Li/S battery with the reduced graphene oxide/activated carbon functional interlayer

The high-energy lithium/sulfur(Li/S) battery has become a very popular topic of research in recent years due to its high theoretical capacity of 1672 m Ah/g. However, the polysulfide shuttle effect remains of great concern with a great number of publications dedicated to its mitigation. In this contribution, a three-dimensional(3D) reduced graphene oxide/activated carbon(RGO/AC) film, synthesized by a simple hydrothermal method and convenient mechanical pressing, is sandwiched between the separator and the sulfur-based cathode, acting as a functional interlayer to capture and trap polysulfide species. Consequently, the Li/S cell with this interlayer shows an impressive initial discharge capacity of 1078 m Ah/g and a reversible capacity of 655 m Ah/g even after 100 cycles. The RGO/AC interlayer impedes the movement of polysulfide while providing unimpeded channels for lithium ion mass transfer. Therefore, the RGO/AC interlayer with a well-designed structure represents strong potential for high-performance Li/S batteries.

Synergistic Effects of Carbon Nanotube(CNT)and Reduced Graphene Oxide(RGO)on Mechanical and Thermal Properties of ZK61 Alloy

The hybrid of carbon nanotube(CNT)and reduced graphene oxide(RGO)reinforced ZK61 composite was fabricated by a hot extrusion process.Compared with the raw ZK61 alloy and single-reinforced composites,the hybrid-reinforced by RGO+CNT complex exhibited significant enhancements both in mechanical and thermal performance.By adjusting the proportion of RGO and CNT in ZK61 alloy,the obtained optimum ZK61/(0.06 wt%RGO+0.54 wt%CNT)composite exhibited increase of 25.4%in yield strength,26.5%in ultimate tensile strength,104%in failure strain and 30.4%in thermal conductivity,respectively,in comparison with ZK61 alloy.The superior properties of the nano-hybrid composite are attributed to the synergetic effects of RGO and CNT,leading to a uniform dispersion and integrated structure as well as the enhanced interfacial bonding with matrix.The strengthening ability of RGO and CNT was calculated to quantify their individual contribution to the improvement in mechanical and thermal properties of the ZK61 matrix composite.The RGO+CNT hybrids provide a promising way to develop Mg matrix composites with impressive performances.

Synthesis of hydrophobic carbon nanotubes/reduced graphene oxide composite films by flash light irradiation

Carbon nanotubes/graphene composites have superior mechanical, electrical and electrochemistry prop- erties with carbon nanotubes as a hydrophobicity boosting agent. Their extraordinary hydrophobic performance is highly suitable for electrode applications in lithium ion batteries and supercapacitors which often employ organic electrolytes. Also the hydrophobic features enable the oil enrichment for the crude oil separation from seawater. The ever reported synthesis routes towards such a composite either involve complicated multi-step reactions, e.g., chemical vapor depositions, or lead to insufficient extru- sion of carbon nanotubes in the chemical reductions of graphene oxide, e.g., fully embedding between the compact graphene oxide sheets. As a consequence, the formation of standalone carbon nanotubes over graphene sheets remains of high interests. Herein we use the facile flash light irradiation method to induce the reduction of graphene oxides in the presence of carbon nanotubes. Photographs, micrographs, X-ray diffraction, infrared spectroscopy and thermogravimetric analysis all indicate that graphene oxides has been reduced. And the contact angle tests confirm the excellent hydrophobic perfor- mances of the synthesized carbon nanotube/reduced graphene oxide composite films. This one-step treatment represents a straightforward and high efficiency way for the reduction of carbon nanotubes/graphene oxides composites.

Influence of tool rotation speeds on mechanical and morphological properties of friction stir processed nano hybrid composite of MWCNT-Graphene-AZ31 magnesium

The ever-increasing demand for light weighted hard materials for transportation industries encouraged researchers to develop composites with excellent mechanical properties which can transform it into more economical and eco-friendly.Reinforcing the metals with carbonaceous nanomaterials are progressively in focus due to their excellent capability to inculcate and tailor the properties of MMCs.In the present research,a hybrid nanocomposite of MWCNT-Graphene-AZ31 Mg alloy has been developed by using variable tool rotation speeds with friction stir processing(FSP).Optimized reinforcement ratio of 1.6%vol.MWCNT and 0.3%vol.of graphene have been used with variable tool rotation speeds,whereas other processing parameters are kept constant.The developed specimens were investigated using standard testing equipment for evaluating and comparing the mechanical properties on the basis of the microstructure of the processing regions and their morphological analysis,according to the ASTM standards.The obtained results revealed an improvement of 19.72%in microhardness and 77.5% of compressive strength in comparison with the base metal AZ 31 Magnesium alloy,with a tool rotational speed of 1400rpm.The values of tensile stress and percentage area reduction were recorded as less than that of the base metal matrix,but an increasing trend has been observed in the values of both with the improvement on rotational speeds of the tool.The effectual strengthening mechanisms are analyzed on the bases of SEM images and observed that discussed and found that grain refinement strengthening is the major contributor to the strength of the nanocomposite.

Toxicity of graphene oxide and multi-walled carbon nanotubes against human cells and zebrafish

Graphene possesses unique physical and chemical properties, which have inspired a wide range of potential biomedical applications. However, little is known about the adverse effects of graphene on the human body and ecological environment. The purpose of our work is to make assessment on the toxicity of graphene oxide (GO) against human cell line (human bone marrow neuroblastoma cell line and human epithelial carcinoma cell line) and zebrafish (Danio rerio) by comparing the toxic effects of GO with its sister, multi-walled carbon nanotubes (MWNTs). The results show that GO has a moderate toxicity to organisms since it can induce minor (about 20%) cell growth inhibition and slight hatching delay of zebrafish embryos at a dosage of 50 mg/L, but did not result in significant increase of apoptosis in embryo, while MWNTs exhibit acute toxicity leading to a strong inhibition of cell proliferation and serious morphological defects in developing embryos even at relatively low concentration of 25 mg/L. The distinctive toxicity of GO and MWNTs should be ascribed to the different models of interaction between nanomaterials and organisms, which arises from the different geometric structures of nanomaterials. Collectively, our work suggests that GO does actual toxicity to organisms posing potential environmental risks and the result is also shedding light on the geometrical structure-dependent toxicity of graphitic nanomaterials.

A Novel Multiscale Reinforcement by In-Situ Growing Carbon Nanotubes on Graphene Oxide Grafted Carbon Fibers and Its Reinforced Carbon/Carbon Composites with Improved Tensile Properties

In-situ growing carbon nanotubes （CNTs） directly on carbon fibers （CFs） always lead to a degraded tensile strength of CFs and then a poor fiber-dominated mechanical property of carbon/carbon composites （C/ Cs）. To solve this issue, here, a novel carbon fiber-based multiscale reinforcement is reported. To synthesize it, carbon fibers （CFs） have been first grafted by graphene oxide （GO）, and then carbon nanotubes （CNTs） have been in-situ grown on GO-grafted CFs by catalytic chemical vapor deposition. Characterizations on this novel reinforcement show that GO grafting cannot only nondestructively improve the surface chemical activity of CFs but also protect CFs against the high-temperature corrosion of metal catalyst during CNT growth, which maintains their tensile properties. Tensile property tests for unidirectional C/Cs with different preforms show that this novel reinforcement can endow C/C with improved tensile properties, 32% and 87% higher than that of pure C/C and C/C only doped with in-situ grown CNTs. This work would open up a possibility to fabricate multiscale C/Cs with excellent global performance.

Reduced Graphene Oxide/Carbon Fiber Composite Membrane for Self-floating Solar-thermal Steam Production

Solar-thermal water evaporation has attracted increasing attention owing to the promising potential to solve the global clean water and energy crisis.But,the development of this strategy is limited by the lack of materials with high solar-thernal conversion efficiency,local heating of superficial water,easy preparation and low cost.Herein,we proposed a facile strategy to prepare a reduced graphene oxide/carbon fiber composite membrane,denoted as RGO/CF membrane.The surface of the RGO/CF membrane was highly hydrophobic,endowing the composite membrane with the self-floating ability on the water without any assistance.The light absorbance ability achieved as high as ca.98%in the wavelength range of 300-1200 nm.The steam evaporation efliciency under the illumination of3-sun was 97%,generating water steam at a rate of 4.54 kg·m^-2·h^-1.Moreover,the solar-thermal steam production rate showed high stability during successive 30 cvcle tests.

Synthesis, Characterization and Gas Sensing Properties of Graphene Oxide-Multiwalled Carbon Nanotube Composite

Graphene oxide （GO）-multiwalled carbon nanotube （MWCNT） composite was synthesized and characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, micro Raman, Fourier transform infrared and ultraviolet-visible near infrared spectroscopy techniques. Spectral characteris- tics of cladding modified fiber optic gas sensors were studied for various concentrations of ammonia, ethanol and methanol at 27 ℃. Thickness of the gas sensing layer was controlled by varying the concentration of composite in ethanol medium （0.5 and 1 mg/mL） for three times dipping process. The O.S mg/ mL concentrated GO-MWCNT coated sensor showed 1.20, 1.40 and 1.15 times higher sensitivity than the GO coated sensor for ammonia, ethanol and methanol vapors, respectively. Furthermore, it exhibited 1.50, 1.80 and 1.80 times better sensitivity than 1 mg/mL concentrated GO-MWCNT coated sensor for ammonia, ethanol and methanol vapors, respectively. The presence of functional groups in GO increased the sen- sitivity. This is mainly attributed to the effective electron charge transfer between the composite materials and analytes.

Electrochemical detection and degradation of ibuprofen from water on multi-walled carbon nanotubes-epoxy composite electrode

This work describes the electrochemical behaviour of ibuprofen on two types of multi-walled carbon nanotubes based composite electrodes, i.e., multi-walled carbon nanotubes-epoxy （MWCNT） and silver-modified zeolite-multi-wailed carbon nanotubes-epoxy （AgZMWCNT） composites electrodes. The composite electrodes were obtained using two-roll mill procedure. SEM images of surfaces of the composites revealed a homogeneous distribution of the composite components within the epoxy matrix. AgZMWCNT composite electrode exhibited the better electrical conductivity and larger electroactive surface area. The electrochemical determination of ibuprofen （IBP） was achieved using AgZMWCNT by cyclic voltammetry, differential-pulsed voltammetry, square-wave voltammetry and chronoamperometry. The IBP degradation occurred on both composite electrodes under controlled electrolysis at 1.2 and 1.75 V vs. Ag/AgCl, and IBP concentration was determined comparatively by differential-pulsed voltammetry, under optimized conditions using AgZMWCNT electrode and UV-Vis spectrophotometry methods to determine the IBP degradation performance for each electrode. AgZMWCNT electrode exhibited a dual character allowing a double application in IBP degradation process and its control.

石墨烯-碳纳米管复合纤维高灵敏度测温性能

以碳纳米管(CNT)为填料、氧化石墨烯(GO)溶液为主体,通过化学限域水热法制备了含有不同质量碳纳米管的石墨烯-碳纳米管复合纤维。发现石墨烯-碳纳米管复合纤维热电性能随着氧化石墨烯与碳纳米管质量比的增加有提升趋势。利用瞬态电热(TET)技术研究了石墨烯-碳纳米管复合纤维的测温性能,并分析了其导电机理。结果表明,石墨烯-碳纳米管复合纤维的测温性能表现良好,且随着温度的降低,测温性能进一步提升。在30 K时,电阻温度系数(TCR)为0.05 K^(-1),特征响应时间为0.56 s;电流热退火后结构尺寸增大了0.5倍。导电机理由热激活传导(150~292 K)转变为最近邻跳跃(NNH)传导(70~150 K)和可变范围跳跃(VRH)传导(30~70 K)。为石墨烯-碳纳米管复合纤维在高灵敏度温度传感器上的应用提供了理论支撑。

多维碳材料/聚氨酯复合材料的制备、力学性能及功能性

文中采用异氟尔酮二异氰酸酯对氧化石墨烯(GO)和羟基碳纳米管(OH-MWCNTs)混合碳材料接枝改性,制备出NCO官能团接枝的MWCNTs-g-GO高活性多维碳材料及新型聚氨酯复合材料。研究了MWCNTs-g-GO多维碳材料对力学性能、老化行为和导电性的影响。由X射线衍射分析得出,改性后混合碳材料中GO的层间距由0.87 nm扩大到1.71 nm,碳纳米管缠结程度明显降低,有效提升了碳纳米材料的分散性;随着多维MWCNTs-g-GO含量的增加,对聚氨酯进行了力学性能测试,其硬度、定伸强度逐渐增加,断裂伸长率单调降低,拉伸强度则先增大后减小;当其含量为0.05%时,拉伸强度较空白样提高23%,增大到48.7 MPa;老化150℃×5 d后,衰减率约为26.3%;当含量为0.20%时,电导率约为6.12×10^(-4) S/cm,是空白样的76倍。多维碳纳米材料较单一碳材料对聚氨酯表现出优异的增强、抗热氧和导电等作用。

碳纳米管/还原氧化石墨烯/聚氨酯电热变色传感纱线的制备及其性能

为了解决柔性应变传感器灵敏度较差、应变范围较窄、牢度不高等问题,设计了一种以聚氨酯细丝为芯,以碳纳米管和还原氧化石墨烯构成的三维导电网络为鞘的应变传感纱线,并采用热致变色油墨为保护层,使应变传感纱线兼具变色功能。通过扫描电子显微镜、X射线衍射仪、傅里叶红外光谱仪对传感纱线形貌与结构进行表征,并使用电子万能测试机和万能拉力试验机测试了柔性应变传感器的传感性能和稳定性能。结果表明:碳纳米管穿插于还原氧化石墨烯片层间,形成了导电性能良好的三维导电网络;变色传感纱线灵敏度最高达32.31,应变范围可达100%,可用于人体微小运动检测;在4 V的低电压下即可迅速升温至60℃,能够实现主动变色的附加功能,为发展变色响应快、颜色可调控、使用稳定性高的热致变色材料和传感材料提供新的设计思路,推动碳纳米材料在柔性可穿戴领域的应用。

CNT/rGO复合三维非织造材料基柔性压力传感器的制备及性能

针对织物基柔性压力传感器灵敏度低、响应范围窄和制备工艺复杂的问题,以自制的三维热熔纤维非织造材料为基材,采用超声波辅助浸渍碳纳米管(CNT)和还原氧化石墨烯(rGO)协同修饰纤维表面,构建出具备高灵敏度和耐久性的三维热熔非织造材料基压力传感器,并对该传感器的结构形貌、传感性能和健康监测性能等进行测试。结果表明,该传感器具有高灵敏度(在0~9.28 kPa监测压强范围内,灵敏度为2.33×10^(-2) kPa^(-1))、快速响应/回复时间(70 ms/90 ms)、宽感测范围(0~227 kPa)和优异的循环耐久性(约16000次循环)。该传感器可以用于人体健康监测、运动监测和语音监测等领域。

多孔氮化碳/石墨烯复合材料的实验制备

设计了多孔氮化碳/石墨烯复合材料的制备实验,利用三聚氰胺与氯化钠共混煅烧得到多孔氮化碳(FCN)后,以多孔氮化碳(FCN)与氧化石墨烯(GO)为基体,通过水热法合成三维多孔功能氮化碳/还原氧化石墨烯(FCN/RGO)复合材料。利用X射线衍射仪、扫描电子显微镜表征了FCN/RGO的内部结构和微观形貌,并通过电化学工作站分析了FCN/RGO的电化学性能。分析结果表明,与传统的块状氮化碳/还原氧化石墨烯(BCN/RGO)相比,FCN/RGO的电化学性能有显著提升,在电流密度为0.5 A/g时,比电容达到277 F/g,与BCN/RGO相比提升了29.4%;且在经过1000圈循环后比电容保持率依旧达99.1%。FCN/RGO复合材料组装的电容器充电后可点亮红色LED灯,在超级电容器电极材料领域具有一定的应用潜力。

氨基醇改性GO/CNTs复合气凝胶的制备及对盐湖卤水硼的吸附

分离和提取盐湖卤水中的低浓度硼,可提高资源综合利用率,亦有利于解决盐湖下游产品的硼杂质干扰问题。采用水热法合成氧化石墨烯/碳纳米管(GO/CNTs)复合气凝胶,通过环氧开环反应将多羟基的2-氨基-1,3-丙二醇接枝到气凝胶表面,得到氨基醇改性的氧化石墨烯/碳纳米管(GO/CNTs)气凝胶硼吸附剂,采用FT-IR、XPS和SEM对硼吸附剂形貌结构等进行表征分析。考察pH、初始浓度、温度和接触时间等因素对硼吸附的影响,研究发现,吸附剂在孔道内和表面均具有丰富多元醇基团的多孔结构,pH=10、硼初始质量浓度C_(0)=1200 mg/L时对硼最大平衡吸附量达到43.42 mg/g,在35℃下吸附硼性能最佳,60 min内可达饱和吸附平衡,吸附过程符合准二阶动力学模型。吸附机理为硼与多羟基之间的化学络合作用。该吸附剂在卤水中硼的分离方面展现出良好的应用价值和潜力。

二次掺杂制备聚苯胺/石墨烯/碳纳米管复合材料及其防腐性能

在高氯酸体系中通过原位聚合将苯胺(ANI)单体分别与还原氧化石墨烯(RGO)、碳纳米管(CNTs)制备了一次掺杂态产物PANI/RGO和PANI/CNTs,产物分别经氨水解掺杂后,在高氯酸体系中经二次掺杂制备得到二次掺杂态聚苯胺/石墨烯/碳纳米管(Redoped PANI/RGO/CNTs)复合材料。通过扫描电镜、透射电镜、傅里叶变换红外光谱和紫外光谱对其不同产物形貌和结构进行表征,通过电化学工作站测试了不同产物在3.5%NaCl溶液的防腐蚀性能。结果表明,在RGO与ANI质量比为1:20、CNTs与ANI质量比为1:20时,二次掺杂态产物中聚苯胺纳米纤维可分别在RGO和CNTs上均匀生长并形成网状结构,纤维长度达到850 nm,形貌均一,其防腐蚀性能最优异,缓蚀效率可达81.79%。通过二次掺杂将PANI/RGO和PANI/CNTs复合制备Redoped PANI/RGO/CNTs材料,可有效避免石墨烯和碳纳米管在制备复合材料过程中的团聚,得到结构规整、防腐性能更优异的复合材料。

氧化石墨烯-多壁碳纳米管-漆酚甲醛聚合物制备及性能研究

本研究通过两步法制备了改性氧化石墨烯-多壁碳纳米管-漆酚甲醛聚合物(GOMWCNT/UFP)复合涂料。采用辊涂法将复合涂料应用于金属基材表面,进行结构性能表征,考察复合涂层的物理机械性能和耐电化学腐蚀性能。与纯漆酚缩甲醛(UFP)和MWCNT/UFP相比,GO-MWCNT/UFP复合涂层的物理力学性能(附着力和硬度)和抗电化学腐蚀性均得到明显改善。GO-MWCNT/UFP复合涂层的附着力等级和硬度分别达到1级和6H,腐蚀效率低至1.62×10^(−5),防腐效率高达99.70%。研究结果表明,GO(氧化石墨烯)通过共价键合与MWCNT结合,均匀分散于UFP中,明显提高了UFP涂层的物理力学性能和防腐蚀性。

氧化石墨烯/碳纳米管对几种典型高分子材料的性能影响

氧化石墨烯/碳纳米管(GO/CNTs)作为理想的碳纳米材料,拥有独特三维空间结构和巨大的比表面积,被广泛应用于增强高分子材料,可提升复合材料物理力学性能、稳定性,并赋予复合材料优异的导热、导电、动态力学等性能。本文介绍了常用于制备GO/CNTs基的制备方法,重点对比了铸层/涂覆法、真空抽滤法、共混法制备复合材料的微观形貌与优缺点,探讨了结构控制与GO/CNTs基复合材料性能的关系,详细介绍了GO的改性、CNTs的改性和GO/CNTs的掺杂与高分子材料的相容性,并对其在环氧树脂、橡胶、可生物降解聚合物的应用进行了分析,探究GO/CNTs对复合材料物理力学性能和功能性的影响,最后总结了GO/CNTs改性高分子材料的技术优势及目前存在的问题,展望未来发展方向,以期对GO/CNTs改性环氧树脂、橡胶等高分子材料制备高附加值产品提供参考。

基于纳米复合材料修饰的玻碳电极检测血清中糖类抗原125

构建基于氮掺杂还原氧化石墨烯@羧基化多壁碳纳米管(N-rGO@CMWCNT)和壳聚糖@金纳米颗粒(CS@AuNP)修饰的电化学免疫传感器检测血清中糖类抗原125(CA125)。将N-rGO@CMWCNT和CS@AuNP依次修饰在玻碳电极表面,二者可通过化学作用稳定结合;再将CA125抗体孵育在电极表面,抗体与AuNP形成金硫键(Au—S),可用于检测CA125抗原,采用差分脉冲伏安法(DPV)检测不同浓度CA125所对应的电信号。扫描电子显微镜(SEM)图显示N-rGO@CMWCNT和CS@AuNP的成功合成,Raman光谱表明氮元素成功掺杂于碳纳米复合材料,线性循环伏安法(CV)曲线显示免疫传感器的成功构建。在最优实验条件下,该传感器对CA125检测线性范围为1 mU/mL~100 U/mL,检出限低至0.4 mU/mL,样品的加标回收率在94.5%~107.7%之间,同时其可在10天内保持稳定。该方法精密性好、准确度高、抗干扰能力强,可应用于肺癌患者血清中CA125的检测。