Self-assembly morphology effects on the crystallization of semicrystalline block copolymer thin film.
Self-assembly morphology effects on the crystallization of semicrystalline block copolymer thin film.
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DOI：
10.1063/1.2711437
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发表时间：
2007-03
期刊：
影响因子：
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通讯作者：
Yuhan Wei;C. Pan;Bin-yao Li;Yanchun Han
中科院分区：
文献类型：
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作者：
Yuhan Wei;C. Pan;Bin-yao Li;Yanchun Han
研究了自组装形态对聚苯乙烯-聚乳酸非对称半结晶嵌段共聚物薄膜结晶行为的影响。首先，通过提高溶剂选择性，制备了一系列不同的自组装聚集体，从球形到椭圆形和菱形层状胶束（两种不同的菱形胶束，定义为菱形1和菱形2）。然后，这些自组装聚集体在薄膜演化的早期阶段的结晶的影响进行了研究，通过原位热台原子力显微镜。随着温度的升高，从球形胶束和晶面扁平的树枝晶开始出现异质成核。在高温下，观察到突出的结构，由于增厚的平坦的晶体，并最终形成更稳定的结晶。菱形层状胶束的退火导致不同的现象。龟壳状晶体结构从菱形胶束1的外围开始，并在大部分非晶畴内部的存在下遍布整个膜表面。菱形片层胶束2的表面出现侵蚀和小孔，没有出现类似菱形1的结晶。结果表明，两种胶束中分子链的折叠程度不同，导致了不同的退火行为。
Self-assembly morphology effects on the crystalline behavior of asymmetric semicrystalline block copolymer polystyrene-block-poly(L-lactic acid) thin film were investigated. Firstly, a series of distinctive self-assembly aggregates, from spherical to ellipsoid and rhombic lamellar micelles (two different kinds of rhombic micelles, defined as rhomb 1 and rhomb 2) was prepared by means of promoting the solvent selectivity. Then, the effects of these self-assembly aggregates on crystallization at the early stage of film evolution were investigated by in situ hot stage atomic force microscopy. Heterogeneous nucleation initiated from the spherical micelles and dendrites with flat on crystals appeared with increasing temperature. At high temperature, protruding structures were observed due to the thickening of the flat-on crystals and finally more thermodynamically stable crystallization formed. Annealing the rhombic lamellar micelles resulted in different phenomena. Turtle-shell-like crystalline structure initiated from the periphery of the rhombic micelle 1 and spread over the whole film surface in the presence of mostly noncrystalline domain interior. Erosion and small hole appeared at the surface of the rhombic lamellar micelle 2; no crystallization like that in rhomb 1 occurred. It indicated that the chain-folding degree was different in these two micelles, which resulted in different annealing behaviors.