Perforated layer structures in liquid crystalline rod-coil block copolymers.
Perforated layer structures in liquid crystalline rod-coil block copolymers.
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DOI：
10.1021/ja053548k
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发表时间：
2005-10
影响因子：
15
通讯作者：
K. Tenneti;Xiaofang Chen;Christopher Y. Li;Y. Tu;X. Wan;Qifeng Zhou;I. Šics;B. Hsiao
中科院分区：
文献类型：
--
作者：
K. Tenneti;Xiaofang Chen;Christopher Y. Li;Y. Tu;X. Wan;Qifeng Zhou;I. Šics;B. Hsiao
本文报道了在一系列棒状-螺旋状液晶嵌段共聚物（BCP）-聚（苯乙烯-嵌段-（2，5-二[4-甲氧基苯基]氧羰基）苯乙烯）（PS-b-PMPCS）中观察到的四元穿孔层结构。PMPCS形成刚性杆，而PS形成线圈组。差示扫描量热法（DSC）、偏振光显微镜（PLM）、小角X射线散射（SAXS）、广角X射线衍射（WAXD）和透射电子显微镜（TEM）技术被用于研究这些棒-线圈分子，并且在相对低分子量（M（w））下在f（PMPCS）约0.37处观察到穿孔层结构。样品和约0.5 in高M（w）PS-b-PMPCS。这种实质性的相边界移动归因于BCP的棒-线圈性质。穿孔服从四边形而不是六边形对称。在样品PS（272）-b-PMPCS（93）（f（PMPCS）约为0.52）中，在真实的空间中也观察到穿孔的“开始”，其中很少有PS链打断PMPCS层。通过与PS均聚物共混，f（PS）的略微增加导致BCP形态的急剧变化，并且在f（PMPCS）约0.48处观察到均匀的四齿穿孔。
We report a novel observation of the tetragonal perforated layer structures in a series of rod-coil liquid crystalline block copolymers (BCPs), poly(styrene-block-(2,5-bis[4-methoxyphenyl]oxycarbonyl)styrene) (PS-b-PMPCS). PMPCS forms rigid rods while PS forms the coil block. Differential scanning calorimetry (DSC), polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), wide-angle X-ray diffraction (WAXD), and transmission electron microscopy (TEM) techniques were used to investigate these rod-coil molecules, and a perforated layer structure was observed at f(PMPCS) approximately 0.37 in relatively low molecular weight (M(w)) samples and approximately 0.5 in high M(w) PS-b-PMPCS. This substantial phase boundary shift was attributed to the rod-coil nature of the BCP. The perforation obeys a tetragonal instead of hexagonal symmetry. The "onset" of perforation was also observed in real space in sample PS(272)-b-PMPCS(93) (f(PMPCS) approximately 0.52), in which few PS chains punctuate PMPCS layers. A slight increase in f(PS), by blending with PS homopolymer, led to a dramatic change in the BCP morphology, and uniform tetragonal perforations were observed at f(PMPCS) approximately 0.48.