Controlling the Growth of Stacks of Correlated Lamellar Crystals of a Block Copolymer
Controlling the Growth of Stacks of Correlated Lamellar Crystals of a Block Copolymer
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DOI：
10.1021/acs.macromol.9b02120
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发表时间：
2019-12
期刊：
影响因子：
5.5
通讯作者：
Sumit Majumder;R. Reiter;Jun Xu;G. Reiter
中科院分区：
文献类型：
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作者：
Sumit Majumder;R. Reiter;Jun Xu;G. Reiter
在聚合物的结晶过程中，除了单层聚合物晶体外，还经常观察到具有独特取向和单晶特征的相关片层堆叠。然而，对于这种堆积，我们仍然缺乏一个通用的标准，即聚合物晶体的垂直生长。在这里，通过在基薄片的折叠表面上采用自诱导成核来产生适当的种子，我们确定了允许控制嵌段共聚物晶体薄片堆叠形成的实验条件。采用两步结晶工艺，使叠片的成核和生长条件解耦，有利于聚合物晶体在薄膜中垂直生长。为了观察相关片层堆积的形成，需要有足够的熔融聚合物储层，并结合基底片层的缓慢横向生长。采用这种方法，我们能够形成高度约为初始薄膜厚度10倍的堆栈。
In the crystallization of polymers, besides monolamellar polymer crystals, stacks of correlated lamellae with a unique orientation and signatures of single crystals have often been observed. However, we still lack a generic criterion for such stacking, that is, vertical growth of polymer crystals. Here, by employing self-induced nucleation on the fold surface of a basal lamella for generating appropriate seeds, we identify experimental conditions allowing for a controlled formation of stacks of crystalline lamellae of a block copolymer. Adopting a two-step crystallization procedure, we decoupled nucleation and growth conditions of stacked lamellae and thereby favored vertical growth of polymer crystals in thin films. A sufficient reservoir of molten polymers in combination with slow lateral growth of the basal lamella is required for observing the formation of stacks of correlated lamellae. Taking this path, we were able to form stacks reaching heights of about 10 times the initial film thickness.