中文摘要：

利用混合强酸对多壁碳纳米管（MWCNTs）进行氧化浸泡处理。采用透射电镜、原子力显微镜、Raman光谱、红外光谱等分析手段对处理前后的MWCNTs进行表征，探索氧化浸泡时间对MWCNTs微观形貌及剪断过程的影响，并对氧化剪断后短碳管在水溶液中的分散性进行研究。结果表明，MWCNTs在混酸中浸泡72h左右可以使其从缺陷处剪断，形成管长为200～1500nm的短直管，且碳管表面及端口处嫁接上羟基和羧基活性基团。由于极性官能团的存在，使得MWCNTs的等电点从4．5下降到3．5，沉降实验和分光光度测试显示短碳管在有适量阴离子型表面活性剂存在的pH-2的水溶液中超声振荡40min后具有良好的分散效果。

英文摘要：

Multi-wall carbon nanotubes （MWCNTs） were oxidized by soaking in mixed acids. Their microstructure and composi- tion were characterized using transmission electron microscopy, atomic force microscopy, Raman spectroscopy and infrared spectros- copy. The influence of soaking time on microstructure and dispersibility of the cut MWCNTs in aqueous solution was investigated. Results show that the MWCNTs were oxidized at defect sites by the mixed acids and converted from highly tangled ropeS into short, open-ended nanotubes with lengths of 200-1500 nm. The isoelectric point was reduced from 4.5 to 3.5 due to hydroxyl and carboxyl groups on the surface and the open ends of the cut MWCNTs. The aggregation experiments and UV-vis absorbance spectra revealed that the cut MWCNTs can be best dispersed in an aqueous solution containing 0.1 wt. % of sodium dodecyl-benzenesulfonate when sonicated at a pH value of 2 for 40 rain.