碳纳米管氧化成环制备研究

Fabrication of carbon nanotube rings

采用化学气相沉积方法制备的碳纳米管,用酸溶液进行弱氧化处理,经适当温度在大气中烧灼后碳纳米管发生弯曲,在样品中出现大量的环状结构.利用原子力显微镜、透射电子显微镜和扫描电子显微镜对典型环直径为300nm的碳纳米管环进行了表征.烧灼温度和烧灼时间对环的结构和产率有重要的影响.实验数据统计结果表明,烧灼温度在510—530℃区间内可得到超过40%的碳纳米管环产率,并且烧灼时间延长到120min有利于提高碳纳米管环的产率.在加热情况下,碳纳米管端结合的羧基官能团脱水成酯,导致弯曲的碳纳米管结合成环.

Nanotube rings were fabricated with a high yield by heating the lightly etched carbon nanotubes under ambient conditions that were produced by chemical vapor deposition method. These rings, typically 300 nm in diameter, were characterized using atomic force microscopy, transmission electron microscopy and scanning electron microscopy. The structure and yield of nanotube rings depended strongly on the heating temperature and time. Our researches suggest that the optimal heating temperature ranges from 510 degrees C to 530 degrees C, and that the heating time up to 120 min is favorable for the increase of the yield. At high temperatures, the esterification of carboxyl functional groups attached at the nanotube ends resulted in the bending of straight nanotubes into closed rings.