Shi Lei, Yanagi Kazuhiro, Cao Kecheng, Kaiser Ute, Ayala Paola, Pichler Thomas
Faculty of Physics , University of Vienna , 1090 Wien , Austria.
Department of Physics , Tokyo Metropolitan University , 1-1 Minami-Osawa , Hachiouji, Tokyo 192-0397 , Japan.
ACS Nano. 2018 Aug 28;12(8):8477-8484. doi: 10.1021/acsnano.8b04006. Epub 2018 Aug 9.
Linear carbon chains (LCCs) have been shown to grow inside double-walled carbon nanotubes (DWCNTs), but isolating them from this hosting material represents one of the most challenging tasks toward applications. Herein we report the extraction and separation of LCCs inside single-walled carbon nanotubes (LCCs@SWCNTs) extracted from a double-walled host LCCs@DWCNTs by applying a combined tip-ultrasonic and density gradient ultracentrifugation (DGU) process. High-resolution transmission electron microscopy, optical absorption, and Raman spectroscopy show that not only short LCCs but clearly long LCCs (LLCCs) can be extracted and separated from the host. Moreover, the LLCCs can even be condensed by DGU. The Raman spectral frequency of LCCs remains almost unchanged regardless of the presence of the outer tube of the DWCNTs. This suggests that the major importance of the outer tubes is making the whole synthesis viable. We have also been able to observe the interaction between the LCCs and the inner tubes of DWCNTs, playing a major role in modifying the optical properties of LCCs. Our extraction method suggests the possibility toward the complete isolation of LCCs from CNTs.
线性碳链（LCCs）已被证明能在双壁碳纳米管（DWCNTs）内部生长，但将它们与这种主体材料分离是应用中最具挑战性的任务之一。在此，我们报告了通过应用尖端超声和密度梯度超速离心（DGU）相结合的方法，从双壁主体LCCs@DWCNTs中提取并分离出单壁碳纳米管内部的LCCs（LCCs@SWCNTs）。高分辨率透射电子显微镜、光吸收和拉曼光谱表明，不仅短的LCCs，而且明显长的LCCs（LLCCs）都可以从主体中提取并分离出来。此外，LLCCs甚至可以通过DGU浓缩。无论DWCNTs的外管是否存在，LCCs的拉曼光谱频率几乎保持不变。这表明外管的主要重要性在于使整个合成可行。我们还能够观察到LCCs与DWCNTs内管之间的相互作用，这在改变LCCs的光学性质方面起着主要作用。我们的提取方法表明了从碳纳米管中完全分离LCCs的可能性。
