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Thickness-Dependent Order-to-Order Transitions of Bolaform-like Giant Surfactant in Thin Films
Macromolecules ( IF 5.1 ) Pub Date : 2017-09-11 00:00:00 , DOI: 10.1021/acs.macromol.7b01598
Chih-Hao Hsu , Kan Yue , Jing Wang , Xue-Hui Dong , Yanfeng Xia , Zhang Jiang 1 , Edwin L. Thomas 2 , Stephen Z. D. Cheng
Affiliation  

Controlling self-assembled nanostructures in thin films allows the bottom-up fabrication of ordered nanoscale patterns. Here we report the unique thickness-dependent phase behavior in thin films of a bolaform-like giant surfactant, which consists of butyl- and hydroxyl-functionalized polyhedral oligomeric silsesquioxane (BPOSS and DPOSS) cages telechelically located at the chain ends of a polystyrene (PS) chain with 28 repeating monomers on average. In the bulk, BPOSS-PS28-DPOSS forms a double gyroid (DG) phase. Both grazing incidence small-angle X-ray scattering and transmission electron microscopy techniques are combined to elucidate the thin film structures. Interestingly, films with thicknesses thinner than 200 nm exhibit an irreversible phase transition from hexagonal perforated layer (HPL) to compressed hexagonally packed cylinders (c-HEX) at 130 °C, while films with thickness larger than 200 nm show an irreversible transition from HPL to DG at 200 °C. The thickness-controlled transition pathway suggests possibilities to obtain diverse patterns via thin film self-assembly.

中文翻译:

薄膜中Bolaform状表面活性剂的厚度依赖性的阶跃转变

通过控制薄膜中的自组装纳米结构,可以自底向上制造有序的纳米级图案。在这里,我们报告了类似硼酸的巨型表面活性剂薄膜的独特的厚度依赖性相行为,该表面活性剂由丁基和羟基官能化的多面体低聚倍半硅氧烷(BPOSS和DPOSS)笼式螯合地位于聚苯乙烯(PS)的链端)链平均包含28个重复单体。大量,BPOSS-PS 28-DPOSS形成双螺旋(DG)相。掠入射小角X射线散射技术和透射电子显微镜技术相结合,阐明了薄膜结构。有趣的是,厚度小于200 nm的薄膜在130°C时从六角形穿孔层(HPL)到压缩的六角形填充圆柱体(c-HEX)发生不可逆的相变,而厚度大于200 nm的薄膜则显示从HPL不可逆的相变在200°C下蒸馏至DG。厚度控制的过渡路径暗示了通过薄膜自组装获得不同图案的可能性。
更新日期:2017-09-11
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