Carbon nanotubes were synthesized by using a nanostructured conducting polymer—the polypyrrole nanofiber via microwave radiation. The radiation time was set to be 30, 60, and 90 seconds, respectively. The morphological evolvements of the as-synthesized carbon nanotubes with increased radiation time (e.g., shape, diameter, wall structure, and catalyst size) were carefully investigated, and the possible growth mode was discussed in detail. It was found that the growth mode of the carbon nanotubes synthesized from the conducting polymer substrate under microwave radiation was complex and cannot be simply interpreted by either a “tip” or “base” growth model. A new growth mode of the “liquifying cascade growth” was observed for the as-synthesized carbon nanotubes, as their growth was directed by a series of liquified iron nanoparticles with sequentially decreasing sizes, similar to the cascade of liquid droplets. And it could provide useful insights for the morphological and structural designs of the carbon nanotubes prepared by related microwave-based methods.

中文翻译：

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使用导电聚合物纳米纤维合成的碳纳米管的形态演变

碳纳米管是通过使用纳米结构的导电聚合物-聚吡咯纳米纤维经微波辐射合成的。辐射时间分别设置为30、60和90秒。仔细研究了随着辐射时间（例如形状，直径，壁结构和催化剂尺寸）的增加，合成后的碳纳米管的形态演变，并详细讨论了可能的生长方式。发现在微波辐射下由导电聚合物基底合成的碳纳米管的生长模式是复杂的，并且不能简单地用“尖端”或“基础”生长模型来解释。对于合成后的碳纳米管，观察到一种新的“液化级联生长”生长模式，因为它们的生长是由一系列大小逐渐减小的液化铁纳米颗粒所控制的，类似于液滴的级联。它可以为通过相关微波方法制备的碳纳米管的形态和结构设计提供有用的见识。