碳纳米管的修饰及吸附性能研究

【作者】 朱双美；

【导师】 赵元黎；

【作者基本信息】 郑州大学 ， 光学， 2007， 硕士

【摘要】 碳纳米管(CNTs)作为一种理想的一维纳米材料，由于其具有丰富的空隙结构、大的比表面积和很高的表面能，在传感器领域具有广阔的应用前景。研究表明碳纳米管吸附生物分子具有良好的生物相容性和较快电子传递速率，因而是一种潜在的生物传感器材料。论文主要开展了碳纳米管酸处理对其电学性能和光学性能的影响，重点研究了碳纳米管吸附甘氨酸和胆固醇对其电学性能和光学性能的影响。本论文采用催化热解二甲苯的方法制备出多壁碳纳米管。对混酸(浓硫酸和浓硝酸体积比为3：1)处理的碳纳米管进行扫描电镜、透射电镜、傅立叶红外光谱和拉曼光谱分析和表征，结果发现经过混酸处理后的碳纳米管的端头被打开，长度被切断，并接上了羧基等官能团，成为羧基修饰的碳纳米管。以磁控贱射的方法在玻璃基底上制作叉指银电极，使用丝网印刷的方法在玻璃基底上将碳纳米管制备成膜。通过伏安特性曲线和四探针实验法，分别对混酸处理前后碳纳米管膜电阻进行了测试，结果显示混酸处理后膜电阻变大。在空气氛围下，对混酸处理前后碳纳米管膜电阻随存放时间变化关系进行了实验。结果显示，膜电阻在开始阶段迅速升高，随着时间的增加，上升趋势变缓，呈现出先升后降的现象，最后趋于稳定。通过测试室温下吸附甘氨酸前后碳纳米管膜伏安特性曲线和体积电阻率，发现吸附过甘氨酸后，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。对碳纳米管吸附甘氨酸后电性能的变化机理和甘氨酸的生物性能进行了一些初步的探讨。对吸附甘氨酸前后碳纳米管膜进行拉曼光谱表征，显示在吸附甘氨酸之前碳纳米管的I_D／I_G=0.6804，而在吸附甘氨酸之后碳纳米管的I_D／I_G=0.8958，后者为前者的1.33倍。并且D带和G带都发生了不同程度的频移，反映吸附甘氨酸之后碳纳米管缺陷增多。试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。以同样的方法测试了在室温下吸附胆固醇前后碳纳米管膜伏安特性曲线和电阻率，发现吸附了胆固醇后碳纳米管的导电能力减弱，且减弱的幅度与胆固醇的浓度有关。对吸附胆固醇前后碳纳米管膜进行拉曼光谱表征：由于碳纳米管的结构缺陷及由于结构缺陷在管壁上吸附的胆固醇产生的缺陷使得拉曼信息发生变化。更多还原

【Abstract】 As one of the perfect one-dimensional nano-materials, carbon nanotube has porous microstructure with high area and energy, which makes it a promising gas sensing material. Some report suggested that CNT could enhance electro-transfer of adsorption biology molecule greatly, so it can become a kind of potential material for biology sensor. This paper studies the chemical and optic influence of chemically treated of carbon nanotube films in experiment, and emphasizes the electric mechanism and Raman spectrum effects of the CNTs after glycine and cholesterol adsorbed treatment.Carbon nanotubes , synthesized by pyrolysis of xylene., studied by SEM, TEM and Raman spectroscopy. Based on the above studies, The chemical modification of carbon nanotubes was carried out using the mixture of oil of vitriol and nitric acid treatment methods. These modified carbon nanotubes were characterized by TEM image、FTIR spectra and Raman spectroscopy. The result find the end of Cabon nanotubes was unclosed and become carboxyl-treated Carbon nanotubes because of engaging the carboxyl. Multi-wall carbon nanotubes by using screen print was spread on the interdigitated Ag electrodes, which was splashed by magnetron sputtering. Through the V-I curves experiment and the four-probe experiment, we tested The electrical conductivity of the dried carbon nanotubes films. Film resistances both treated and untreated carbon nanotubes were studied,respectively. The results showed that film resistances of treated carbon nanotubes largen. Deposited time of treated carbon nanotubes effects on resistance were explored as well. Film resistances increased rapidly at the beginning stage, and slowly increased before reduction, moved toward stability with the passage of time.The electrical conductivity of the dried carbon nanotubes film increased when the electrode was exposed to glycin, and the increasing amplitude of conductivity is associated with the glycin concentration. The mechanism that the conductivity of carbon nanotube films changes when glycin is absorbed is discussed preliminary. Raman Spectral analyses present a contrast between carbon nanotube films which the electrode was exposed to glycin and untreated ones. The result show that the I_D/I_G is 0.6804 and 0.8958 of carbon nanotubes before and after glycine adsorption, respectively.Moreover, both D band and G band have undergone varying degrees of frequency shift.This Experimental result indicates that multi-wall cabon nanotubes is a promising sensing material for glycin detection at room temperature.The electrical conductivity of the dried carbon nanotubes film decreased when the electrode was exposed to cholesterol, and the decreasing amplitude of conductivity is concerned with the cholesterol concentration. Electronic properties about carbon nanotube films after cholesterol adsorbed treatment were theoretically analyzed. Raman Spectral analyses present a contrast between carbon nanotube films which the electrode was exposed to cholesterol and untreated ones. Structural defects and Cholesterol absorption of defects because of Structural defects Make changes Raman spectroscopy of carbon nanotubes.更多还原