Defect Patterns from Controlled Heterogeneous Nucleations by Polygonal Confinements
Defect Patterns from Controlled Heterogeneous Nucleations by Polygonal Confinements
复制标题
多边形限制受控异质成核的缺陷模式
DOI：
10.1021/acs.langmuir.8b00101
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发表时间：
2018
期刊：
影响因子：
3.9
通讯作者：
Li Weihua
中科院分区：
文献类型：
--
作者：
Yang Tao;Zhu Yu;Xue Haiyan;Li Weihua
在晶体结构中经常观察到缺陷。如何调节缺陷的形成或消失提出了一个有趣的问题。在这项工作中，我们提出了一种由规则分布的稳定“程序化缺陷”组成的缺陷图案的方法，该方法是通过从均匀状态到六边形图案的非均相成核来进行的。采用时间相关的金兹堡-朗道理论对多边形约束下ab -二嵌段/ c -均聚物共混体系的成核过程进行了建模，并用细胞动力学模拟对其进行了模拟。具体来说，我们通过与六边形晶格存在角不匹配的三种多边形约束（包括正方形、五边形和八边形）来证明该方法的有效性。多边形的每个角或边分别诱导成核事件。两个相邻的角或边的两个成核畴晶粒表现出不相称的取向，因此它们的合并导致以5 - 7对形式聚集缺陷的径向线。因此，这些径向线构成了缺陷的径向图案，它们的数量等于多边形的边数。5 - 7对缺陷的距离是由相邻晶粒之间不相称的角度决定的，这与硬晶体中的缺陷相似。该方法可以通过对成核剂进行编程，使其超越简单的多边形限制，从而扩展到制造各种缺陷图案。
Defects are often observed in crystalline structures. To regulate the formation or annihilation of defects presents an interesting question. In this work, we propose a method to fabricate defect patterns composed of regularly distributed steady “programmed defects”, which is proceeded via the heterogeneous nucleation of a hexagonal pattern from a homogeneous state. The nucleation process occurring in a model system of AB-diblock/C-homopolymer blends under polygonal confinement is modeled by the time-dependent Ginzburg–Landau theory and is simulated by the cell dynamics simulations. Specifically, we demonstrate the validity of this method by means of three polygonal confinements including square, pentagon, and octagon, which have mismatched angles with the hexagonal lattice. Each corner or side of the polygons induces a nucleation event separately. Two nucleated domain grains by two neighboring corners or sides exhibit incommensurate orientations, and thus their merging leads to a radial line of clustered defects in the form of five–seven pairs. As a result, these radial lines constitute a radial pattern of defects, and their number is equal to the side number of the polygon. The distance of five–seven defect pairs is dictated by the incommensurate angle between two neighboring grains, which is similar to that of defects in hard crystals. This method can be extended to fabricate diverse defect patterns by programming the nucleation agents beyond simple polygonal confinements.