Defect structures and ordering behaviours of diblock copolymers self-assembling on spherical substrates.
Defect structures and ordering behaviours of diblock copolymers self-assembling on spherical substrates.
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DOI：
10.1039/c4sm01180e
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发表时间：
2014-08
期刊：
影响因子：
3.4
通讯作者：
Liangshun Zhang;Liquan Wang;Jiaping Lin
中科院分区：
文献类型：
--
作者：
Liangshun Zhang;Liquan Wang;Jiaping Lin
约束于曲面上的有序结构的主要区别之一是拓扑缺陷的性质。本文用Landau-Braovskii理论研究了球形衬底上嵌段共聚物层状相和柱状相的缺陷结构和有序性，并用球谐基的高精度谱方法进行了数值求解。对于柱状相，在球形衬底上会产生孤立的倾斜和疤痕。疤痕中过剩位错的数量与球体半径成线性关系。表征有序化动力学的缺陷分数呈指数衰减。这些疤痕是由孤立的倾斜通过微小的疤痕形成的。对于片层相，识别出三种类型的缺陷结构(刺激型、螺旋型和准棒型)。位错湮没是片层相的主要有序化机制。
One of the main differences of ordered structures constrained on curved surfaces is the nature of topological defects. We here explore the defect structures and ordering behaviours of both lamellar and cylindrical phases of block copolymers confined on spherical substrates by the Landau-Brazovskii theory, which is numerically solved by a highly accurate spectral method with a spherical harmonic basis. For the cylindrical phase, isolated disclinations and scars are generated on the spherical substrates. The number of excess dislocations in a scar depends linearly on the sphere radius. The defect fraction characterizing the ordering dynamics decays exponentially. The scars are formed from the isolated disclinations via mini-scars. For the lamellar phase, three types of defect structures (hedgehog, spiral and quasi-baseball) are identified. The disclination annihilation is the primary ordering mechanism of the lamellar phase.