Effects of polydispersity on phase behavior of diblock copolymers
Effects of polydispersity on phase behavior of diblock copolymers
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DOI：
10.1021/ma060717s
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发表时间：
2006-09-19
期刊：
影响因子：
5.5
通讯作者：
Shi, An-Chang
中科院分区：
文献类型：
--
作者：
Cooke, David M.;Shi, An-Chang
采用自洽场理论模型研究了多分散性对二嵌段共聚物熔体相行为的影响。以多分散指数kappa = M-w/M-n - 1为扰动参数，建立了多分散体系的微扰理论。用互反空间法构造相图。发现有序-无序过渡边界向更高的温度移动，正如随机相近似分析所预测的那样。对于不对称聚合物分布，多分散性倾向于具有弯曲界面的结构。有序结构的畴间距随着多分散度指数的增加而增大。对自由能的分析提供了对这些效应机理的理解。
The influence of polydispersity on the phase behavior of diblock copolymer melts is studied using a self-consistent field theoretic model. A perturbation theory is developed for the polydisperse system, in which the polydispersity index, kappa = M-w/M-n - 1, is taken as a perturbation parameter. Phase diagrams are constructed using the reciprocal space method. It is found that the order-disorder transition boundary shifts to higher temperatures, as predicted by a random phase approximation analysis. For asymmetric polymer distributions, polydispersity favors structures with curved interfaces. The domain spacing of the ordered structures increases with increasing polydispersity index. An analysis of the free energy provides an understanding of the mechanism of these effects.