Hole nucleation and growth induced by crystallization and microphase separation of thin semicrystalline diblock copolymer films
Hole nucleation and growth induced by crystallization and microphase separation of thin semicrystalline diblock copolymer films
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DOI：
10.1021/ma0357366
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发表时间：
2004-09-07
期刊：
影响因子：
5.5
通讯作者：
Han, YC
中科院分区：
文献类型：
--
作者：
Fu, J;Cong, Y;Han, YC
我们研究了薄晶圈-二嵌段共聚物薄膜在结晶过程中诱导的空穴成核和生长。中性/选择性二元溶剂的半结晶棒状组件用作种子，在高于玻璃化转变温度（T-g）但低于熔点（T-m）的温度下形成结晶核。纳米棒的结晶驱动邻近的共聚物链扩散到生长的纳米棒中。共聚物链的耗竭在纳米棒的边缘产生孔洞成核和生长。同时，未结合成纳米棒的聚合物链通过自由表面和衬底的感应定向，导致孔深度限制在片层间距，类似于20 nm。孔洞和纳米棒生长为t(alpha)，其中t是退火时间，在指数a中发现交叉。共聚物链在表面和界面上的取向和拉伸加速了结晶，而后者又加速了孔洞的生长速度。在T b> T-m时，晶粒熔化，共聚物链松弛并流入薄膜的第一层。
We have investigated the hole nucleation and growth induced by crystallization of thin crystalline-coil diblock copolymer films. Semicrystalline rodlike assemblies from neutral/selective binary solvent are used as seeds to nucleate crystallization at temperatures above the glass transition temperature (T-g) but below melting point (T-m). The crystallization of nanorods drives neighboring copolymer chains to diffuse into the growing nanorods. Depletion of copolymer chains yields hole nucleation and growth at the edge of the nanorods. Simultaneously, the polymer chains unassociated into the nanorods were oriented by induction from the free surface and the substrate, leading to limitation of the hole depth to the lamellar spacing, similar to20 nm. The holes, as well as the nanorods, grow as t(alpha), where t is the annealing time and a crossover in the exponent a. is found. The orientation and stretching of the copolymer chains by the surface and interface are believed to accelerate the crystallization, and in turn, the latter accelerates the growth rate of the holes. At T > T-m, the grains melt and the copolymer chains relax and flow into the first layer of the film.