Substrate Roughness Speeds Up Segmental Dynamics of Thin Polymer Films
Substrate Roughness Speeds Up Segmental Dynamics of Thin Polymer Films
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DOI：
10.1103/physrevlett.124.027802
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发表时间：
2020-01-15
影响因子：
8.6
通讯作者：
Napolitano, Simone
中科院分区：
文献类型：
--
作者：
Panagopoulou, Anna;Rodriguez-Tinoco, Cristian;Napolitano, Simone
我们发现，在非平衡条件下制备的聚（4-氯苯乙烯）薄膜的链段流动性得到增强，在粗糙的基板附近。这种趋势是在现有的粗糙度的治疗，得出结论，它是一个来源较慢的动力学，并测量薄膜的聚（2-乙烯基吡啶），其动力学是粗糙度不变的。我们的实验证据表明，更快的界面动力学起源于界面密度的减少，由于不完全填充的基板凹凸。重要的是，我们的研究结果同意相同的缩放，描述了散装材料的密度依赖性，相关的链段迁移率的一个术语指数的特定体积，并与经验关系链接的玻璃化转变温度的增加，更大的界面能。
We show that the segmental mobility of thin films of poly(4-chlorostyrene) prepared under non-equilibrium conditions gets enhanced in the proximity of rough substrates. This trend is in contrast to existing treatments of roughness which conclude it is a source of slower dynamics, and to measurements of thin films of poly(2-vinylpiridine), whose dynamics is roughness invariant. Our experimental evidence indicates the faster interfacial dynamics originate from a reduction in interfacial density, due to the noncomplete filling of substrate asperities. Importantly, our results agree with the same scaling that describes the density dependence of bulk materials, correlating segmental mobility to a term exponential in the specific volume, and with empirical relations linking an increase in glass transition temperature to larger interfacial energy.