In situ atomic force microscopy of the melting of melt-crystallized polyethylene
In situ atomic force microscopy of the melting of melt-crystallized polyethylene
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DOI：
10.1016/j.polymer.2005.02.133
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发表时间：
2006-07
期刊：
影响因子：
4.6
通讯作者：
J. Hobbs
中科院分区：
文献类型：
--
作者：
J. Hobbs
采用高温原子力显微镜实时观察熔体原位结晶聚乙烯片层的熔化过程。有取向和无取向的样品都被观察到。实现了羊肉串结构的熔化，包括露出裸露的定向羊肉串。观察到薄片从其边缘熔化，这被认为是由于晶体边缘固有的更高的迁移率，而不是由于不同程度的结晶后完善而导致晶体内部稳定性的差异。对生长过程中观察到的结构熔化的观察证实，材料在较低温度下结晶首先熔化，其次是材料在受限几何形状中结晶，最后其余的等温结晶片从边缘融化回来，具有明显随机的形态，而不是生长过程的相反。在熔融过程中的原位观察被确认为蚀刻的替代和补充技术，以揭示结晶过程中的行为，当结晶速度太快而无法进行原位观察时。
High temperature AFM is used to observe the melting of polyethylene lamellae crystallized from the melt in situ in real-time. Both oriented and un-oriented samples are observed. The melting of shish–kebab structures, including revealing the bare oriented shish, is achieved. Lamellae are observed to melt from their edges, and this is proposed to be due to the inherent higher mobility at the crystal edges rather than differences in stability within the crystal due to different levels of post crystallization perfecting. Observation of the melting of structures that have been observed during growth confirms that material crystallized at lower temperatures melts first, followed by material crystallized in confined geometries, and finally the rest of the isothermally crystallized lamellae that melt back from the edges with an apparently random morphology that is not the reverse of the growth process. In situ observation during melting is confirmed as an alternative and complementary technique to etching to reveal behaviour during crystallization when crystallization is too rapid for in situ observation.