吸附甘氨酸对多壁碳纳米管电性能的影响

以磁控贱射的方法在玻璃基底上制作叉指银电极,用丝网印刷技术制备碳纳米管膜。室温下测试吸附甘氨酸前后碳纳米管膜伏安特性和电阻率的变化,发现吸附了甘氨酸后碳纳米管的导电能力增加,且增加的幅度与甘氨酸的浓度有关。实验结果预示:碳纳米管是一种良好的室温下检测甘氨酸的敏感材料。对碳纳米管吸附甘氨酸前后电性能的变化机理进行了初步的探讨。     

鸟嘌呤和8-羟基脱氧鸟嘌呤核苷在聚甘氨酸修饰电极上的电化学行为及其同时测定

在优化的实验条件下,利用电化学方法制备了甘氨酸修饰电极,对修饰膜的电活性进行了表征.用循环伏安法研究了鸟嘌呤(G)和8一羟基脱氧鸟嘌呤核苷(8-OH-dG)在聚甘氨酸修饰电极上的电化学行为,并建立了对两者进行分别检测和同时检测的分析方法.实验结果表明,聚甘氨酸修饰电极可以增强鸟嘌呤和8-羟基脱氧鸟嘌呤核苷在电极表面的吸附,并且可以加快鸟嘌呤和8-羟基脱氧鸟嘌呤核苷在电极表面的电子传输,使两种电活性物质在聚甘氨酸修饰电极上的电化学信号明显增大,检测灵敏度大大提高,并且该修饰电极具有良好的稳定性和重现性.可用于鸟嘌呤和8-羟基脱氧鸟嘌呤核昔的分别和同时检测.     

碳纳米管修饰电极研究鸟嘌呤及其核苷的电化学行为及测定

利用微波辅助功能化的单壁碳纳米管可以均匀分散于二次水中,并可以在玻碳电极表面形成稳定的薄膜,利用该修饰电极研究了鸟嘌呤与鸟嘌呤核苷的电化学行为及其测定,并对鸟嘌呤和鸟嘌呤核苷的分别或同时测定条件进行了优化.结果表明,与裸玻碳电极相比,鸟嘌呤及其核苷在该单壁碳纳米管修饰电极上的氧化峰电流和检测灵敏度大大提高,该方法检出限低、分析速度快.酸降解的DNA在该修饰电极上可以得到对应鸟嘌呤的灵敏溶出峰,峰电流与DNA浓度在一定范围内成线性关系.     

微膜尺寸与吸附物对微膜生化传感器动态特性的影响

以微膜生化传感器为研究对象,利用ADINA软件进行模态分析,获得了微膜生化传感器在液态介质影响下的固有频率,分析了微膜结构尺寸和吸附物对传感器动态性能的影响。研究表明：微膜生化传感器的固有频率随着微膜厚度的增大而增大,随着微膜半径的增大而减小。吸附物质量使传感器的固有频率降低,吸附物的吸附位置也对传感器的固有频率产生影响。     

基于碳纳米管／壳聚糖／纳米金活性界面的辣根过氧化物酶传感器研制

利用壳聚糖(Chitosan)的成膜性能以及碳纳米管在其中良好的分散性,在玻碳电极表面首先形成碳纳米管/壳聚糖膜,通过膜表面丰富的氨基与纳米金的强静电吸附,在玻碳电极表面获得稳定的纳米Au修饰层,吸附固定辣根过氧化物酶(HRP),制得无需电子媒介的H2O2生物传感器.循环伏安曲线显示,当加入H2O2溶液后,阴极峰电流增大,而阳极电流相应减少,表明通过碳纳米管/壳聚糖/纳米金活性界面固定在玻碳电极表面的HRP与电极之间有良好的直接电子传导能力,对H2O2的还原具有良好的电催化活性,H2O2的测定线性范围为5×10-5～2.7×10-3mol/L.     

基于铂纳米颗粒修饰碳纳米管Nafion膜电极的葡萄糖传感器

将分散在Nafion溶液中的多壁碳纳米管(MWNT)修饰玻碳电极(GCE),再在该膜上电沉积一层铂纳米粒子,制成铂纳米颗粒修饰的碳纳米管Nafion膜电极(Nafion-MWNT-Pt/GCE),并吸附固定葡萄糖氧化酶(GOD),构建电流型葡萄糖生物传感器。考察了Nafion-MWNT-Pt/GCE的电化学特性,发现沉积铂纳米粒子后,Fe(CN)6-3/-4电对在Nafion-MWNT-Pt/GCE上的氧化峰和还原蜂之间的电势差(ΔE)为179mV,小于未修饰铂纳米粒子的碳纳米管Nafion膜电极的ΔE(190mV),表明碳纳米管上电沉积的铂纳米粒子可加速电极的电子传递,电化学反应具有良好的可逆性。此外,铂纳米粒子尚具有良好的催化H2O2氧化的特性,H2O2在Nafion-MWNT-Pt/GCE上的计时电流响应明显增大。基于Nafion-MWNT-Pt/GCE的葡萄糖生物传感器显示了良好的传感性能,其检测线性范围为2.1×10-5～7.6×10-3mol/L,检测下限为1.0×10-6mol/L。     

基于碳纳米管场发射的压力传感器仿真与设计

碳纳米管是场发射阴极的极佳材料.基于碳纳米管和金属铜的复合电镀技术,采用有限元软件对压力传感器的碳纳米管布设进行了有限元仿真,使用模拟退火算法对阳极变形膜的尺寸进行了优化,并设计了实现压力传感器的工艺过程.碳纳米管的管径在不影响电镀质量的情况下可尽量小,选取的长度不影响直立,间距在500 nm时可获得最大电流.阳极膜的...     

羟基--碳纳米管气体传感器气敏性的仿真研究

采用羟基修饰后的碳纳米管作为气体传感器的气敏材料,会使其响应灵敏度提高。利用密度泛函理论研究了两种气体分子（ Cl2和H2 S）在本征单壁碳纳米管（ SWCNT）和羟基修饰过的单壁碳纳米管（ SWCNT—OH）上的吸附。分析其态密度图,并尝试改变气体分子在碳纳米管上的吸附位置与方向,从吸附能的大小、电荷转移量的多少、吸附距离的远近上,为本征SWCNT,SWCNT—OH的气敏性和两种气体在碳纳米管上的最佳吸附位置姿态提供对比与理论分析。     

基于MWCNTs的气敏测试纸

介绍了一种简单、可直接在纸上制作的气体传感测试纸.由多壁碳纳米管(MWCNTs)在纸上摩擦,粘附的MWCNTs即为传感器的敏感层.采用相同方法分别在不同的纸张上制作传感器,并对气敏性能进行了比较,结果表明:滤纸的多孔性和粗糙的表面,可以促使其上的敏感层吸附和释放气体分子,使气体传感器在室温条件下完全恢复.传感器具有良好的重复性和稳定性.气体传感测试纸可以进一步用于挥发性有机气体(VOCs)的检测开发.     

基于MWCNTs/Nafion复合膜的高性能声表面波湿敏传感器研究

湿度检测广泛应用于工业、医疗等各个领域,对高性能湿度传感器的需求日趋迫切。首先对声表面波传感器敏感机理进行了深入的分析,得到影响其性能的主要因素。在此基础上研制出一种以多壁碳纳米管(MWCNTs)和Nafion复合材料为湿敏膜,高频声表面波谐振器为换能元件的高性能湿敏传感器。实验表明,制得的湿敏传感器在宽湿度范围内(1...     

基于SEM图像的碳纳米管薄膜均匀性表征方法研究

将多壁碳纳米管综合了超声处理和高速离心等分散工艺单分散后,采用喷射吸滤法制备碳纳米管薄膜,并研究超声时间对薄膜分布均匀性的影响.基于多重分形理论和SEM图像分析多壁碳纳米管薄膜的形态学特征.碳纳米管薄膜的分布均匀性主要取决于多重分形谱宽度Δa和最大、最小概率子集维数的差别ΔF等分形参数.多重分形分析弥补了传统的表面评价和统计分析的不足.该碳纳米管薄膜均匀性表征方法将为碳纳米管薄膜的制备提供指导.     

Contact dynamics of nanodroplets in carbon nanotubes: effects of electric field,tube radius,and salt ions

We report contact dynamics of nanodroplets in carbon nanotubes using molecular dynamics simulations. The effects of electric field, nanotube radius, and salt ions included in the nanodroplets are explored in more detail. For the cases without applied electric field, the droplet fills the cross section of carbon nanotubes with small radius completely. When the tube radius becomes larger, the droplet retracts towards the surface of the nanotube to minimize the surface tension of the droplet and shows wider extension along the axial direction. When an electric field perpendicular to the axial direction of the carbon nanotubes is applied, the position and shape of the droplets are changed which is also related to the tube radius and whether the droplet contains salt ions. Unlike a planar surface, the nanotube limits spreading of the droplets along the radial direction. The variation of the center of mass of the droplets indicates a significant confinement to the position of the droplets in the electric field. For the salty water droplets, a strong electric field induces ejection of small water clusters from the droplet in a nanotube with large radius. As a consequence, the droplet and water clusters are separated and moved to two opposite sides of the nanotube by the electric field.     

基于多壁纳米碳管的传感器对甲苯的气敏性研究

传感器的基底为Al2O3,上面真空溅射了叉指金电极,在电极之间涂布微量多壁纳米碳管悬浊液,干燥后作为气敏膜.室温下测试电极暴露于甲苯气体前后的电阻变化,发现吸附了甲苯后电极的导电能力下降,且下降的幅度与被测甲苯浓度有良好的线性关系.该实验结果预示着多壁纳米碳管是一种良好的室温下检测甲苯的敏感材料.对该气敏响应的产生机理本文进行了一些初步的探讨.     

Carbon‐nanotube electron emitters for display applications

Abstract— The optoelectronic, mechanical, and thermal properties of carbon nanotubes have made them very attractive for a wide range of potential applications. However, many applications require the growth of aligned/micropatterned carbon nanotubes with or without a modified nanotube surface. We have developed several simple pyrolytic methods for large‐scale production of aligned carbon‐nanotube arrays perpendicular to the substrate surface. We have also used photolithographic and soft‐lithographic techniques to pattern our aligned carbon nanotubes with submicron resolution. These aligned carbon‐nanotube arrays can be transferred onto various substrates of particular interest (e.g., on conducting substrates as electron emitters for flat‐panel displays) in either a patterned or non‐patterned fashion. The well‐aligned structure further allows us to prepare aligned coaxial nanowires of carbon nanotubes sheathed with polymers and to modify the surface of individual carbon nanotubes by plasma treatment. These aligned/micropatterned carbon nanotubes with and without surface modification possess desirable properties for electron emission applications.     

Fundamental dynamics of flow through carbon nanotube membranes

The flow of a model non-polar liquid through small carbon nanotubes is studied using non-equilibrium molecular dynamics simulation. We explain how a membrane of small-diameter nanotubes can transport this liquid faster than a membrane consisting of larger-diameter nanotubes. This effect is shown to be back-pressure dependent, and the reasons for this are explored. The flow through the very smallest nanotubes is shown to depend strongly on the depth of the potential inside, suggesting atomic separation can be based on carbon interaction strength as well as physical size. Finally, we demonstrate how increasing the back-pressure can counter-intuitively result in lower exit velocities from a nanotube. Such studies are crucial for optimisation of nanotube membranes.     

碳纳米管修饰电极的制备及其电化学敏感性研究

介绍了一种碳纳米管修饰电极的制备工艺,并对其电化学敏感性进行测试和分析.该工艺辅助聚合物聚酰亚胺,利用机械球磨、可控刻蚀等工艺,实现了碳纳米管的均一分布,露出碳纳米管的断口和缺陷.在玻碳电极上涂覆碳纳米管/聚酰亚胺复合膜,结合扫描电子显微镜观察,得到了可控、均一、稳定的电极界面.利用循环伏安法对电极进行性能测试,讨论了...     

Single-walled carbon nanotube network/poly composite thin film for flow sensor

A fabrication method about single-walled carbon nanotube (SWCNT) network and polydimethylsiloxane (PDMS) based composite thin film is reported, which can be used as flow sensor cell. This composite thin film is immersed in deionized water and salt solution with different flow rate tests. The morphology of SWCNTs on the surface of the composite thin film is characterized by scanning electron microscopy, revealing the SWCNTs are coated by PDMS chains. The induced voltage generates along the direction of the flowing liquid and depends significantly on the ionic concentration and flow velocity. Since the SWCNTs are fixed into PDMS matrix, the I–V curves of the composite thin film before and after several flow velocity measurements are exactly coincident, and the repeating flow-induced voltage experiment shows the composite thin film has a reliable electric characteristic and wide potential of device application.     

Molecular dynamics simulation of salt rejection through silicon carbide nanotubes as a nanostructure membrane

Salt rejection phenomenon was investigated using armchair silicon carbide (SiC) nanotubes under applied electric fields. The systems included the (7,7) and (8,8) SiC nanotubes surrounded by silicon nitride membrane immersed in a 0.4 mol/L aqueous solution of sodium chloride. Results of molecular dynamics (MD) simulations for selective separation of Na⁺ and Cl⁻ ions showed that the (7,7) SiC nanotube is suitable for separation of cations and the (8,8) SiC nanotube can be used for separating anions. The water desalination by SiC nanotubes was demonstrated by potential of mean force for Na⁺ and Cl⁻ ions in each SiC nanotube. Furthermore, the ionic current, ion residence time, and the radial distribution functions of species were measured to evaluate the properties of the system. Based on the results of this research, the studied SiC nanotubes can be recommended as a nanostructure model for water desalination.