Alignment of dispersed multiwalled carbon nanotubes in low strength AC electrical fields.
Alignment of dispersed multiwalled carbon nanotubes in low strength AC electrical fields.
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低强度交流电场中分散的多壁碳纳米管的排列。
DOI：
10.1166/jnn.2005.098
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发表时间：
2005
影响因子：
--
通讯作者：
E. Grulke
中科院分区：
文献类型：
--
作者：
Jenny Hilding;Ma Hong;E. Grulke
研究了在非离子表面活性剂的帮助下，用电作为工具诱导悬浮在水中的多壁碳纳米管排列的可能性。分别使用15-140 V/cm和0.1-500 Hz的各种场强和频率进行了几个不同的实验。通过反射光显微镜拍摄过程来记录实验。每个影片的长度在15-45秒之间，足以估计定向速率和对准方向。据观察，对准率随着场强的增加而增加，并且系统在较低频率下不太敏感。场强和频率都可以用来控制取向的速度和程度。在低频率下，悬浮液被迫在电极之间以泵送方式振荡。纳米管被迫与流体流线而不是与场线对齐。在更高的频率下，振荡停止。对准率随着场强的增加而增加。对于>或= 70 V/cm的电场和> 20 Hz的频率，MWNT在小于1 s内完全对齐。对非理想MWNT/H2O分散体系进行了类似的实验。观察到MWNT以与之前相同的方式排列，但在几分钟后发生转变。多壁碳纳米管迅速相互靠近，形成了一个主要由对齐的多壁碳纳米管组成的网络。在网络分支出来连接电极后，MWNT的运动减慢了。碳纳米管在外加电场中的排列似乎是一种高效、快速、廉价的方法，具有许多优点。该方法为生产具有独特性能的新型材料打开了许多有趣和令人兴奋的可能性。从工程的角度来看，分离的MWNT的对齐和对齐的MWNT在网络中的创建都是感兴趣的。
The possibilities to use electricity as a tool to induce alignment of multiwall carbon nanotubes suspended in water with help of a non-ionic surfactant have been investigated. Several different experiments were made using various field strengths and frequencies of 15-140 V/cm and 0.1-500 Hz respectively. The experiments were recorded by filming the processes through a reflected light microscope. Each movie is between 15-45 seconds long and is adequate to estimate orientation rates and alignment directions. It was observed that the alignment rate increased with increasing field strength and that the system is less sensitive at lower frequencies. Both field strength and frequency can be used to control the speed and degree of orientation. At low frequencies, the suspension is forced to oscillate in a pumping fashion between the electrodes. The nanotubes are forced to align with the fluid streamlines rather than with the field lines. At higher frequencies, the oscillation ceases. Alignment rate increases with increasing field strengths. The MWNTs are fully aligned in less than 1 s for an electrical field > or = 70 V/cm and frequency > 20 Hz. A similar experiment was carried out for a non-ideal MWNT/H2O dispersion system. It was observed that the MWNTs aligned in the same fashion as before but after a few minutes a transition occurred. The MWNTs moved quickly towards each other and a network consisting of mainly aligned MWNTs was created. The MWNT movement slowed down after the network had branched out to connect the electrodes. The alignment of CNTs in an applied electrical field seems to be an efficient, quick, and cheap method with many advantages. The method opens doors to many interesting and exciting possibilities for production of novel materials with unique properties. Both alignment of separated MWNTs and the creation of aligned MWNTs in networks are of interest from an engineering point of view.