Synthesis of POSS-functionalized liquid crystalline block copolymers via RAFT polymerization for stabilizing blue phase helical soft superstructures
Synthesis of POSS-functionalized liquid crystalline block copolymers via RAFT polymerization for stabilizing blue phase helical soft superstructures
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通过RAFT聚合合成POSS官能化液晶嵌段共聚物以稳定蓝相螺旋软超结构
DOI：
10.1039/c8py00136g
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发表时间：
2018
影响因子：
4.6
通讯作者：
Weian Zhang
中科院分区：
文献类型：
--
作者：
Jianqiu Jin;Mingjie Tang;Zhenghe Zhang;Kang Zhou;Yun Gao;Zhi-Gang Zheng;Weian Zhang
通过可逆加成-断裂转移（RAFT）聚合，首次合成了一系列POSS功能化的液晶嵌段共聚物PHEMAPOSS-b-P6 CBMA，该嵌段共聚物含有一个多面体低聚倍半硅氧烷（POSS）嵌段和一个介晶氰基联苯嵌段，并通过简单的掺杂将其用于稳定蓝相液晶。利用POSS和聚合物的优点，建立了一种新的策略，该策略不同于通常采用的BP聚合物稳定策略。这种新的BP系统具有广泛的BP范围，覆盖典型的室温范围（即25-30 °C），跨越了复杂的加工障碍，这在传统的光诱导聚合物稳定化中是不可避免的。特别是，通过优化掺杂LC BCP的浓度，得到了比普通光聚合稳定BP更低的驱动电压、更低的迟滞和更高的克尔常数（K）。采用差示扫描量热法（DSC）和热重分析（TGA）对共聚物的热性能进行了研究，结果表明POSS的引入有效地提高了共聚物的热稳定性。这种巧妙的策略为形成大尺寸BP显示器和其他在工作过程中与UV光暴露不兼容的设备提供了一种辉煌而简单的方法。
A series of POSS-functionalized liquid crystalline block copolymers (LC BCPs), PHEMAPOSS-b-P6CBMA, containing a crystalline polyhedral oligomeric silsesquioxane (POSS) block and a mesogenic cyanobiphenyl block, were prepared via reversible addition–fragmentation transfer (RAFT) polymerization for the first time and utilized to stabilize blue phase (BP) liquid crystals through facile doping. Using the advantages of both the POSS and polymer, a new strategy, which is distinct from the commonly adopted strategy for polymer stabilization of the BP, has been established. This new BP system with a wide BP range covering the typical room temperature range (i.e. 25–30 °C) leaps over intricate processing barriers, which are inevitable in conventional photo-induced polymer stabilization. In particular, improved electro-optical (E-O) properties of the BP, including lower driving voltage, lower hysteresis and a higher Kerr constant (K) compared with the common BP stabilized via photopolymerization, were obtained by optimizing the concentration of the doped LC BCP. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were employed to evaluate the thermal properties of the LC BCPs, and the results indicated that the introduction of POSS enhanced the thermostabilities of the copolymers effectively. Such an ingenious strategy provides a brilliant and easy way to form large size BP displays and other devices that are incompatible with UV light exposure during the working process.