Phase Behaviors of Multi-tailed B(2)AB(2)-Type Regio-isomeric Giant Surfactants at the Columnar-Spherical Boundary
Phase Behaviors of Multi-tailed B(2)AB(2)-Type Regio-isomeric Giant Surfactants at the Columnar-Spherical Boundary
复制标题
多尾B(2)AB(2)型区域异构巨表面活性剂在柱-球边界的相行为
DOI：
10.1002/cjoc.202100453
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发表时间：
2021
影响因子：
5.4
通讯作者：
Zhang Wen-Bin
中科院分区：
文献类型：
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作者：
Shao Yu;Han Di;Yan Xiaojin;Hou Bo;Li Yiwen;He Jinlin;Fu Qiang;Zhang Wen-Bin
主要观察和结论我们在此报告了多尾B2AB2型区域异构巨型表面活性剂的精确合成和相行为，该表面活性剂由亲水性多面体低聚倍半硅氧烷（POSS）头部和四个疏水性聚苯乙烯（PS）尾部组成。该合成是通过两个连续的“点击”反应完成的，得到一系列具有对位、间位和邻位构型的区域异构巨型表面活性剂S2DS2（其中S是PS尾部的缩写，D是羟基官能化POSS的缩写）。使用分子量为 1.4 kDa 的单一 PS 尾部研究了它们在柱状-球形边界处的相结构和相行为。具体来说，对位异构体和间位异构体显示出六方堆积圆柱相，其有序-无序转变温度略有不同（~120°C和~130°C），邻位异构体在~120°C下表现出从动力学有利的亚稳态十二角准晶相到热力学稳定的σ相的有序转变，并在~140°C进一步转变为无序态。 °C。构建了相图，并根据计算的每个分子的界面面积合理化了它们的差异。这项工作表明，微小的结构差异不仅可以导致单组分大分子中非常规的相形成，而且可以在这些大分子组装体中呈现动态且丰富的相行为。
Main observation and conclusionWe report herein the precision synthesis and phase behaviors of multi‐tailed B2AB2‐type regio‐isomeric giant surfactants consisting of a hydrophilic polyhedral oligomeric silsesquioxane (POSS) head tethered with four hydrophobic polystyrene (PS) tails. The synthesis was accomplished through two sequential “click” reactions to give a series of regio‐isomeric giant surfactants S2DS2(where S is short for PS tails and D for hydroxyl‐functionalized POSS) inpara‐,meta‐, andortho‐configurations. Their phase structures and phase behaviors at the columnar‐spherical boundary were investigated with a single PS tail molecular weight of 1.4 kDa. Specifically, thepara‐ andmeta‐isomers show hexagonally packed cylinders phases with slightly different order‐disorder transition temperatures (~120 °C and ~130 °C) and theortho‐isomer exhibits an order‐order transition from a kinetically favored, metastable dodecagonal quasi‐crystal phase to a thermodynamically stable sigma phase at ~120 °C, as well as a further transition into the disordered state at ~140 °C. The phase diagram was constructed and their differences were rationalized based on the calculated interfacial area per molecule. This work demonstrates that tiny structural disparity could not only lead to unconventional phase formation in single‐component macromolecules, but also render dynamic and rich phase behaviors in these macromolecular assemblies.