Phase behavior of polystyrene-poly(2-vinylpyridine) diblock copolymers
Phase behavior of polystyrene-poly(2-vinylpyridine) diblock copolymers
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DOI：
10.1021/ma951714a
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发表时间：
1996-04
期刊：
影响因子：
5.5
通讯作者：
Mark F. Schulz;A. K. Khandpur;F. Bates;K. Almdal;K. Mortensen;D. Hajduk;S. Gruner
中科院分区：
文献类型：
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作者：
Mark F. Schulz;A. K. Khandpur;F. Bates;K. Almdal;K. Mortensen;D. Hajduk;S. Gruner
我们使用动态力学光谱、透射电子显微镜、小角中子散射和小角X射线散射表征了一系列聚苯乙烯-聚（2-乙烯基吡啶）二嵌段共聚物（Mw ≥ 20 000 g/mol）的相行为。对对称二嵌段（fPS = 0.5）的测量使我们能够估计该系统的Flory-Huggins相互作用参数（χ），我们用它来将我们的发现放在图表上。四个有序的形态（层状，六角穿孔层，双连续立方/gyroid，和六角填充的圆柱体）被发现在组合物范围从35至70体积%的聚苯乙烯。在38体积%苯乙烯时，有序-有序转变将六角穿孔层和Ia 3d/螺旋相分离。剪切取向材料的研究表明，立方微观结构并没有出现增长的层状相的优选方向，在最近的研究结果在其他二嵌段系统。复合相的出现是由于它们之间的成分。
We characterize the phase behavior of a series of polystyrene−poly(2-vinylpyridine) diblock copolymers (Mw ∼ 20 000 g/mol) using dynamic mechanical spectroscopy, transmission electron microscopy, small-angle neutron scattering, and small-angle X-ray scattering. Measurements on symmetric diblocks (fPS = 0.5) permit us to estimate the Flory−Huggins interaction parameter (χ) for this system, which we use to place our findings on a diagram. Four ordered morphologies (lamellae, hexagonally perforated layers, bicontinuous cubic/gyroid, and hexagonally packed cylinders) are found at compositions ranging from 35 to 70 vol % polystyrene. An order−order transition separates the hexagonally perforated layer and Ia3d/gyroid phases at 38 vol % styrene. Studies of shear-oriented material indicate that the cubic microstructure does not appear to grow with a preferred orientation from the layered phase, in contrast to recent findings in other diblock systems. The occurrence of complex phases at compositions between thos...