Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
J Am Chem Soc. 2010 Mar 24;132(11):3932-8. doi: 10.1021/ja910626u.
The outer walls of double-walled carbon nanotubes (DWNTs) were selectively oxidized using a combination of oleum and nitric acid. Intercalation of oleum between bundled DWNTs enabled a homogeneous reaction by equally exposing all outer wall surfaces to the oxidants. At optimized reaction conditions, this double-wall chemistry enabled high water solubility through carboxylic acid functional groups introduced to the outer wall, while leaving the inner tube intact, as shown by Raman scattering and high resolution TEM. These outer wall selectively oxidized DWNTs retained electrical conductivity up to 65% better than thin films of similarly functionalized single-walled carbon nanotubes, which can be attributed to enhanced electrical percolation via the nonoxidized inner tubes.
采用发烟硫酸和硝酸的混合物选择性氧化双壁碳纳米管（DWNTs）的外壁。发烟硫酸插入到捆绑的 DWNTs 之间，通过使所有外壁表面均匀暴露于氧化剂，从而实现均匀反应。在优化的反应条件下，这种双壁化学通过引入外壁的羧酸官能团使产物具有高水溶性，同时使内管保持完整，如拉曼散射和高分辨率 TEM 所示。这些外壁选择性氧化的 DWNTs 的电导率比同样功能化的单壁碳纳米管薄膜提高了 65%以上，这可以归因于未氧化的内管增强了电渗滤。
