Environment Effects on the Charge States of Metallic and Semiconducting SWCNTs during Their Separation by the Electric-Field Induced Layer Formation Method
Environment Effects on the Charge States of Metallic and Semiconducting SWCNTs during Their Separation by the Electric-Field Induced Layer Formation Method
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DOI：
10.1021/acs.jpcc.8b10192
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发表时间：
2019-02-14
影响因子：
3.7
通讯作者：
Saito, Takeshi
中科院分区：
文献类型：
--
作者：
Kuwahara, Yuki;Sasaki, Fusako;Saito, Takeshi
研究了电场诱导成层法分离金属(m-)和半导体(S-)单壁碳纳米管的机理，考察了环境条件，即pH值和表面活性剂浓度对分离过程的影响。时间过程分析表明，在ELF分离过程中，细胞内的pH和表面活性剂浓度变得不均匀。电位测量表明，在特定的pH范围内，S-单壁碳纳米管比m-单壁碳纳米管带更多的负电荷。ELF成层分离m-和S-SWCNTs的机理可归结为作用在SWCNTs上的电泳力和电渗力的动态变化/平衡。从表面活性剂的种类和分子结构两个方面讨论了不同表面活性剂对ELF法的适用性。
The mechanism of separating metallic (m-) and semiconducting (s-) single-walled carbon nanotubes (SWCNTs) by electric-field induced layer formation (ELF) was investigated, by examining effects from the environmental conditions, that is, the pH and surfactant concentration on the separation process. Time course analysis showed that the pH and surfactant concentration in the cell become inhomogeneous during the ELF separation process. The potential measurements revealed that the s-SWCNTs are much more negatively charged than m-SWCNTs in the specific pH range. The mechanism of ELF separation of m- and s-SWCNTs by forming layers is attributed to the dynamic changing/balancing of the electrophoretic and electroosmotic forces acting on the SWCNTs. The applicability of various surfactants for the ELF method was also discussed in terms of the surfactant types and the molecular structures.