Dielectrophoresis of surface conductance modulated single-walled carbon nanotubes using catanionic surfactants
Dielectrophoresis of surface conductance modulated single-walled carbon nanotubes using catanionic surfactants
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DOI：
10.1021/jp055110c
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发表时间：
2006-02-02
影响因子：
3.3
通讯作者：
Baik, S
中科院分区：
文献类型：
--
作者：
Kim, Y;Hong, S;Baik, S
介电电泳在根据电子类型分离纳米管方面受到了相当大的关注。在这里，我们研究的半导体单壁碳纳米管（SWNT）的表面导电性的影响，诱导的离子表面活性剂，介电泳力的符号。半导体单壁碳纳米管的交叉频率迅速增加的粒子和介质之间的电导率比的增加，导致在10 MHz的电场频率的离子表面活性剂悬浮单壁碳纳米管的不完全分离。为了降低电导率比，单壁碳纳米管的表面电荷被中和的阴离子表面活性剂十二烷基硫酸钠（SDS）和阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）的等摩尔混合物，导致在10 MHz的负介电电泳的半导体物种。比较拉曼光谱研究显示金属单壁碳纳米管几乎完全分离。
Dielectrophoresis has received considerable attention for separating nanotubes according to electronic types. Here we examine the effects of surface conductivity of semiconducting single walled carbon nanotubes (SWNT), induced by ionic surfactants, on the sign of dielectrophoretic force. The crossover frequency of semiconducting SWNT increases rapidly as the conductivity ratio between the particle and medium increases, leading to an incomplete separation of ionic surfactant suspended SWNT at an electric field frequency of 10 MHz. To reduce the conductivity ratio, the surface charge of SWNT is neutralized by an equimolar mixture of anionic surfactant sodium dodecyl sulfate (SDS) and cationic surfactant cetyltrimethylammonium bromide (CTAB), resulting in negative dielectrophoresis of semiconducting species at 10 MHz. A comparative Raman spectroscopy study shows a nearly complete separation of metallic SWNT.