Heterogeneity of the segmental dynamics in cylindrical and spherical phases of diblock copolymers
Heterogeneity of the segmental dynamics in cylindrical and spherical phases of diblock copolymers
复制标题
二嵌段共聚物圆柱相和球形相中链段动力学的异质性
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
J. Colmenero
中科院分区：
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作者：
Mohammed Zakaria Slimani;A. Moreno;J. Colmenero
我们用一个简单的微珠弹簧模型模拟了两嵌段共聚物的柱状相和球状相。我们详细地分析了限制在少数域中的组件的结构α驰豫的动态非均匀性。与以前对同一弹珠模型的片层相的研究类似，该分析揭示了在所研究的温度范围内具有中等的迁移率梯度，定性地探索了高达100 ns的时间尺度。因此，在距离域中心不同距离处测量的α松弛时间跨度不到十年。迁移率梯度的空间扩展显然与先前在同一模型的片层相中观察到的一致。迁移率的梯度似乎与区域内的密度梯度无关，后者确实是不存在的。我们已经进行了自浓度和有效浓度的分析，这一概念通常被用来解释聚合物混合物中的α弛豫。
We have performed simulations of a simple bead–spring model for cylindrical and spherical phases of diblock copolymers. We have analyzed in detail the dynamic heterogeneity of the structural α-relaxation of the component confined in the minority domains. In analogy with previous investigations on the lamellar phase of the same bead–spring model, the analysis reveals moderate gradients of mobility in the investigated temperature range, which qualitatively probes time scales up to 100 ns. Thus, α-relaxation times measured at different distances from the domain center spread over less than one decade. The spatial extension of the gradients of mobility is apparently consistent with that previously observed in the lamellar phase of the same model. Gradients of mobility do not seem to be related to gradients of density within the domains, which are indeed absent. We have performed an analysis of self- and effective concentrations, a concept usually invoked to explain the α-relaxation in polymer mixtures and tha...