Hydrogen Bond Interactions Mediate Hierarchical Self-Assembly of POSS-Containing Block Copolymers Blended with Phenolic Resin
Hydrogen Bond Interactions Mediate Hierarchical Self-Assembly of POSS-Containing Block Copolymers Blended with Phenolic Resin
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DOI：
10.1021/ma502180c
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发表时间：
2014-12-23
期刊：
影响因子：
5.5
通讯作者：
Kuo, Shiao-Wei
中科院分区：
文献类型：
--
作者：
Chiou, Chin-Wei;Lin, Yung-Chih;Kuo, Shiao-Wei
采用阴离子活性聚合法制备了不同组成的聚甲基丙烯酸甲酯-b-聚甲基丙烯酸酯多面体低聚硅氧烷（PMMA-b-PMAPOSS）嵌段共聚物。我们采用差示扫描量热法、傅里叶变换红外光谱、小角x射线散射、透射电子显微镜和广角x射线衍射来研究PMMA-b-PMAPOSS嵌段共聚物与酚醛树脂共混的混溶性、特定相互作用和分层自组装。我们发现添加的酚醛树脂通过前者的OH基团和PMAPOSS的C=O基团之间的氢键优先与PMMA嵌段相互作用。换句话说，酚醛树脂的OH基团不与PMAPOSS块的C=O基团相互作用，导致它们的不混溶。因此，这种酚醛/PMMA-b-PMAPOSS共混物表现为均聚物C和不相混的a -B -B二嵌段共聚物的共混物，其中C与B不相混，但与a相互作用良好；因此，随着酚醛树脂含量的增加，它表现出有序的相变。通过二嵌段共聚物段的微相分离，层状自组装形成六边形排列的圆柱形或片层状纳米结构，POSS聚集体排列成垂直于纳米结构方向的六边形晶格。
Poly(methyl methacrylate)-b-poly(methacryloyl polyhedral oligomeric silsesquioxane) (PMMA-b-PMAPOSS) block copolymers of various compositions were prepared through anionic living polymerization. We employed differential scanning calorimetry, Fourier transform infrared spectroscopy, small-angle X-ray scattering, transmission electron microscopy, and wide-angle X-ray diffraction to investigate the miscibility, specific interactions, and hierarchical self-assembly of PMMA-b-PMAPOSS block copolymers blended with a phenolic resin. We found that the added phenolic resin interacted preferentially with the PMMA blocks through hydrogen bonding between the OH groups of the former and the C=O groups of the PMAPOSS. In other words, the OH groups of the phenolic resin did not interact with the C=O groups of the PMAPOSS blocks, resulting in their immiscibility. Accordingly, this phenolic/PMMA-b-PMAPOSS blend behaved as a blend of homopolymer C and immiscible A-b-B diblock copolymer, where C is immiscible with B but interacts favorably with A; therefore, it displayed an orderorder phase transition with increased phenolic resin content. Hierarchical self-assembly led to the formation of hexagonally packed cylindrical or lamellar nanostructures through microphase separation of the diblock copolymer segment, with POSS aggregates packing into a hexagonal lattice oriented perpendicular to the direction of the nanostructures.