Dynamic Monte Carlo simulations of double crystallization accelerated in microdomains of diblock copolymers.
Dynamic Monte Carlo simulations of double crystallization accelerated in microdomains of diblock copolymers.
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DOI：
10.1063/1.3693519
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发表时间：
2012-03
期刊：
影响因子：
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通讯作者：
Yuan Li;Yu Ma;Juan Li;Xiaoming Jiang;Wenbing Hu
中科院分区：
文献类型：
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作者：
Yuan Li;Yu Ma;Juan Li;Xiaoming Jiang;Wenbing Hu
我们报告动态Monte Carlo模拟的微相分离的二嵌段共聚物，研究如何结晶的一个物种可以加速随后的结晶的另一个物种。虽然晶格共聚物模型带来了边界约束的长周期的微区，两个嵌段之间的单分子水平的力平衡及其变化可以在这个简单的方法来揭示。我们发现了两种相反的加速机制：（1）在较高的晶化温度下，一种物种的亚稳层状晶体变厚，牺牲其微相界面面积，使另一种非晶物种的线圈拉伸更大，从而加速后者的后续晶化，使后者具有更有利的构象。(2)而在晶体中允许链滑动的情况下，一种物质的平衡层状晶体在较高温度下变得更薄，牺牲其热稳定性以获得另一种无定形物质的更高构象熵，从而加速后者在块结处具有更强张力的后续结晶。平行的实验情况进行了讨论。
We report dynamic Monte Carlo simulations of microphase separated diblock copolymers, to investigate how crystallization of one species could accelerate the subsequent crystallization of another species. Although the lattice copolymer model brings a boundary constraint to the long periods of microdomains, the single-molecular-level force balance between two blocks and its change can be revealed in this simple approach. We found two contrastable acceleration mechanisms: (1) the metastable lamellar crystals of one species become thicker at higher crystallization temperatures, sacrificing its microphase interfacial area to make a larger coil-stretching of another amorphous species and hence to accelerate subsequent crystallization of the latter with a more favorable conformation. (2) While in the case allowing chain-sliding in the crystal, the equilibrated lamellar crystals of one species become thinner at higher temperatures, sacrificing its thermal stability to gain a higher conformational entropy of another amorphous species and hence to accelerate subsequent crystallization of the latter with a stronger tension at the block junction. Parallel situations of experiments have been discussed.