Design, synthesis, and characterization of a combined main-chain/side-chain liquid-crystalline polymer based on ethyl cellulose
Design, synthesis, and characterization of a combined main-chain/side-chain liquid-crystalline polymer based on ethyl cellulose
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DOI：
10.1007/s10570-009-9392-z
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发表时间：
2010-01
期刊：
影响因子：
5.7
通讯作者：
Tianhui Hu;He-Lou Xie;Jianbo Xiao;Hailiang Zhang;E. Chen
中科院分区：
文献类型：
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作者：
Tianhui Hu;He-Lou Xie;Jianbo Xiao;Hailiang Zhang;E. Chen
成功合成了一种基于含偶氮苯介晶（AzoEC）的乙基纤维素主链的新型主链/侧链组合液晶聚合物。使用质子核磁共振 (1H NMR)、傅里叶变换红外光谱 (FTIR) 和凝胶渗透色谱 (GPC) 对所得具有不同取代度 (DS) 的聚合物进行分子表征。通过热重分析（TGA）研究热稳定性。通过差示扫描量热法 (DSC)、偏光光学显微镜 (POM) 和广角 X 射线衍射 (WAXD) 研究了这些聚合物的相变和液晶行为。结果表明 DS 对这些聚合物的液晶行为有显着影响。低 DS 的 AzoEC 仅显示出与乙基纤维素 (EC) 相似的胆甾相。然而，当 DS 增加到特定值时，AzoEC 开始表现出令人着迷的超分子结构。具有最大DS的AzoEC的超分子结构由EC主链形成的大尺度有序层状结构和偶氮苯介晶形成的小尺度有序结构组成。
A novel combined main-chain/side-chain liquid-crystalline polymer based on an ethyl cellulose main chain containing azobenzene mesogens (AzoEC) was successfully synthesized. Molecular characterization of the resulting polymers with different degrees of substitution (DS) was performed with proton nuclear magnetic resonance (1H NMR), Fourier-transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC). Thermal stability was investigated by thermogravimetric analysis (TGA). The phase transitions and liquid-crystalline behavior of these polymers were investigated by differential-scanning calorimetry (DSC), polarized optical microscopy (POM), and wide-angle X-ray diffraction (WAXD). The results indicate that DS has substantial effect on the liquid-crystalline behavior of these polymers. AzoEC with low DS only shows the cholesteric phase similar to ethyl cellulose (EC). However, when DS increases to a specific value, AzoEC begins to show fascinating supramolecular structures. The supramolecular structure of AzoEC with maximum DS consisted of a large-scale ordered lamellar structure formed by EC main chains and a small-scale ordered structure formed by azobenzene mesogens.