Influence of alkoxy tail length on the self‐organization of hairy‐rod polymers based on mesogen‐jacketed liquid crystalline polymers
Influence of alkoxy tail length on the self‐organization of hairy‐rod polymers based on mesogen‐jacketed liquid crystalline polymers
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DOI：
10.1002/pola.26194
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发表时间：
2012-10
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影响因子：
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通讯作者：
Sheng Chen;Chang-Kai Jie;He-Lou Xie;Hailiang Zhang
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文献类型：
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作者：
Sheng Chen;Chang-Kai Jie;He-Lou Xie;Hailiang Zhang
设计并通过自由基聚合成功地合成了一系列毛杆聚合物聚{2，5-双[（4-烷氧基苯基）氧羰基]苯乙烯}（P-OCm，m= 1，2，4，6，8，10，12，14，16和18）。单体的化学结构经元素分析、~ 1H NMR和~（13）C NMR确证。用1H NMR和凝胶渗透色谱对聚合物进行了表征。通过差示扫描量热法、广角X射线衍射、偏光显微镜和流变测量等技术相结合，研究了聚合物的相结构和相转变。实验结果表明，随着m的增加，P-OCm的自组装行为发生了变化.首先，P-OCm（m= 1，2）仅显示高于Tg的稳定液晶相。其次，随着烷氧基尾长的增加，P-OCm（m= 4，6，8）在Tg以上呈现出凹入的各向同性相，在较高温度下呈现出液晶相。第三，P-OCm（m= 10，12，14，16，18）表现出不寻常的凹入各向同性相，其分离SmA（在低温下）和柱状相（在高温下）。由于微相分离和熵的驱动力，介晶夹套型液晶聚合物首次在一种聚合物中形成近晶相、凹入各向同性相和柱状相。© 2012 Wiley Periodicals，Inc. J Polym Sci Part A：Polym Chem，2012
A series of hairy‐rod polymers, poly{2,5‐bis[(4‐alkoxyphenyl)oxycarbonyl]styrenes} (P‐OCm,m= 1, 2, 4, 6, 8, 10, 12, 14, 16, and 18) were designed and successfully synthesized via free radical polymerization. The chemical structure of the monomers was confirmed by elemental analysis,1H NMR and13C NMR. The molecular characterizations of the polymers were performed with1H NMR and gel permeation chromatography. The phase structures and transitions of the polymers were investigated by the combination of techniques including differential scanning calorimetry, wide‐angle X‐ray diffraction, polarized optical microscopy, and rheological measurement. The experimental results revealed that the self‐assembly behaviors of P‐OCmchanged with the increase inm. First, the P‐OCm(m= 1, 2) showed only a stable liquid crystalline phase aboveTg. Second, with the increasing length of alkoxy tails, the P‐OCm(m= 4, 6, 8) presented a re‐entrant isotropic phase aboveTgand a liquid crystalline phase at higher temperature. Third, the P‐OCm(m= 10, 12, 14, 16, 18) exhibited an unusual re‐entrant isotropic phase which was separating SmA (in low temperature) and columnar phases (in high temperature). It was the first time that mesogen‐jacketed liquid crystalline polymers formed smectic phase, re‐entrant isotropic phase, and columnar phases in one polymer due to the microphase separation and the driving force of the entropy. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012