Experimental Test of the Cooperative Free Volume Rate Model under 1D Confinement: The Interplay of Free Volume, Temperature, and Polymer Film Thickness in Driving Segmental Mobility
Experimental Test of the Cooperative Free Volume Rate Model under 1D Confinement: The Interplay of Free Volume, Temperature, and Polymer Film Thickness in Driving Segmental Mobility
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DOI：
10.1021/acsmacrolett.8b00844
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发表时间：
2019-01-01
影响因子：
7.015
通讯作者：
Napolitano, Simone
中科院分区：
文献类型：
--
作者：
Debot, Alice;White, Ronald P.;Napolitano, Simone
结果表明，能够成功地模拟压力依赖动力学的协同自由体积(CFV)速率模型可以用来描述聚合物在薄膜中(一维约束)分段时间的温度和厚度依赖关系。CFV模型基于激活自由能，该激活自由能随合作节段的数量增加，而合作节段的数量由系统的自由体积决定。在此，我们将CFV模型应用于一维受限聚(4-氯苯乙烯)P4ClS的链段驰豫的新实验结果，发现在所研究的整个温度和厚度范围内都有显著的一致性。这项工作进一步验证了CFV模型的稳健性，该模型将约束对动力学的影响与主体中的压力变化联系起来，并支持约束效应源于局部密度扰动的观点。
We show that the Cooperative Free Volume (CFV) rate model, successful at modeling pressure-dependent dynamics, can be employed to describe the temperature and thickness dependence of the segmental time of polymers confined in thin films (1D confinement). The CFV model is based on an activation free energy that increases with the number of cooperating segments, which is determined by the system's free volume. Here, we apply the CFV model to new experimental results on the segmental relaxation of 1D confined poly(4-chlorostyrene), P4ClS, and find remarkable agreement over the whole temperature and thickness ranges investigated. This work further validates the robustness of the CFV model, which relates the effects of confinement on dynamics to pressure changes in the bulk, and supports the idea that confinement effects originate from local perturbations in density.