Quantifying changes in the low-frequency dynamics of amorphous polymers by 2D correlation mechanical spectroscopy.
Quantifying changes in the low-frequency dynamics of amorphous polymers by 2D correlation mechanical spectroscopy.
复制标题
DOI：
10.1021/jp311652h
复制
发表时间：
2013-01
期刊：
影响因子：
--
通讯作者：
Xuebang Wu;Huaguang Wang;Zhen-Gang Zhu;C. S. Liu
中科院分区：
文献类型：
--
作者：
Xuebang Wu;Huaguang Wang;Zhen-Gang Zhu;C. S. Liu
用二维相关力学谱研究了不同分子量的聚苯乙烯亚劳斯模的长链段动力学。亚Rouse模首先从α弛豫和Rouse模中分离出来，在相同温度T（B）<$1.2T（g）下，它们的动力学变化与α弛豫相似。在T（B）的子劳斯模式的弛豫时间是独立的分子量，并具有约0.1秒的值，表明仅仅弛豫的时间尺度决定了子劳斯模式的动力学变化。根据耦合模型，这种变化是由分子间协同性的强烈增加引起的。本工作为亚Rouse模的分子间耦合性质提供了直接证据，并证明了亚Rouse模的性质类似于α弛豫，这可能为理解聚合物的玻璃化转变提供了新的视角.
The longer segmental dynamics of sub-Rouse modes in polystyrene with different molecular weights has been investigated by 2D correlation mechanical spectroscopy. The sub-Rouse modes were first separated from the α relaxation and Rouse modes, and their dynamics exhibits a similar change at the same temperature, T(B) ≈ 1.2T(g), as the α relaxation. The relaxation time of sub-Rouse modes at T(B) is independent of molecular weight and has a value of about 0.1 s, indicating that solely the time scale of the relaxation determines the change in dynamics of sub-Rouse modes. According to the coupling model, the change is caused by a strong increase in intermolecular cooperativity. The present work provides direct evidence for the intermolecular coupled nature of the sub-Rouse modes and demonstrates that the properties of the sub-Rouse modes resemble those of α relaxation, which could provide a new perspective for understanding the glass transition of polymers.