Self-assembly of semiflexible block copolymers: 2D numerical implementation of self-consistent field theory
Self-assembly of semiflexible block copolymers: 2D numerical implementation of self-consistent field theory
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半柔性嵌段共聚物的自组装：自洽场论的二维数值实现
DOI：
10.1039/c1sm05142c
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发表时间：
2011-01-01
期刊：
影响因子：
3.4
通讯作者：
Yang, Yuliang
中科院分区：
文献类型：
--
作者：
Gao, Jie;Song, Wendi;Yang, Yuliang
采用基于蠕虫链模型的自洽场理论（SCFT），在二维位置空间中研究了棒状-线团嵌段共聚物的相行为。在三维空间中的单位球面上定义了线段方向，采用二十面体三角网格，并借用有限体积算法数值求解球面上的拉普拉斯算子。在Onsager排斥体积相互作用框架下，利用二维空间计算方法，构建了包含各向同性、均相、近晶-A、近晶-C以及附加的非层状结构的棒状-卷曲嵌段共聚物相图，其中微相分离和液晶行为仅由熵驱动.与我们以前的一维空间计算类似，虽然近晶结构在相图中占据了很大的区域，但在我们的二维空间模拟中，在相对高的线圈分数和强的取向相互作用下观察到了四重堆积的椭圆状畴阵列。我们也重新检查zigzag的稳定性，并确认它是一个在SCFT自由能方面的棒状-卷曲共聚物的介稳结构。
The phase behavior of rod-coil diblock copolymers is investigated in a two-dimensional positional space by using self-consistent field theory (SCFT) based on wormlike chain model. The segment orientation is defined on a unit spherical surface in three-dimensional space with an icosahedron triangular mesh and a finite volume algorithm is borrowed to numerically solve the Laplacian on the sphere. By taking advantage of 2D space calculation, the phase diagram including isotropic, nematic, smectic-A, smectic-C and further appended non-lamellar structures is constructed for the rod-coil diblock copolymers within the framework of Onsager excluded-volume interactions, in which microphase separation and liquid crystalline behavior are driven only by the entropy. Similar to our previous 1D space calculations, although smectic structures occupy large region in the phase diagram, tetragonal packed arrays of ellipse like domains in our 2D space simulations is observed at relatively high coil fractions and strong orientational interactions. We also reexamine the stability of zigzag and confirm it as a thermodynamically metastable structure of rod-coil copolymers in terms of the SCFT free energy.