Geometry-controlled interface localization-delocalization transition in block copolymers.
Geometry-controlled interface localization-delocalization transition in block copolymers.
复制标题
嵌段共聚物中几何控制的界面定位-离域转变
DOI：
10.1103/physrevlett.109.087801
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发表时间：
2012
影响因子：
8.6
通讯作者：
M. Müller
中科院分区：
文献类型：
--
作者：
M. Müller
层状共聚物被限制在由两个条纹图案表面组成的厚度薄膜中，这两个条纹图案表面以一个扭转角度相互旋转，形成了记录并对齐各自化学表面图案的层状结构域。两个厚度域由一个类似于扭转晶界的界面分开。当扭转角较小或表面图案选择性较强时，该界面围绕薄膜的中间波动，而界面则局限于其中一个表面，或相反的极限。这两种形态由一个可由扭转角度控制的界面定位-离域转换（ILDT）分离。对于薄膜，我们发现二阶ILDT，而对于大值的ILDT是一阶的。用一个现象学界面哈密顿量将这些发现与对称混合物的ILDT联系起来，并通过分子模拟证实了这些预测。
Lamellar copolymers confined into a film of thicknessby two stripe-patterned surfaces, which are rotated against each other by a twist angle, form lamellar domains that register and align with the respective chemical surface patterns. The two domains of thicknessandare separated by an interface that resembles a twist grain boundary. At small twist anglesor strong selectivity of the surface patterns, this interface fluctuates around the middle of the film,, while the interface is localized at one of the surfaces,or, in the opposite limit. These two morphologies are separated by an interface localization-delocalization transition (ILDT) that can be controlled by the twist angle. For thin films, we find a second-order ILDT while the ILDT is first-order for largevalues. A phenomenological interface Hamiltonian is used to relate the findings to the ILDT of symmetric mixtures, and the predictions are confirmed by molecular simulation.