Self organization of main-chain/side-chain liquid crystalline polymer based on "jacketing" effect with different lengths of spacer: from smectic to hierarchically ordered structure
Self organization of main-chain/side-chain liquid crystalline polymer based on "jacketing" effect with different lengths of spacer: from smectic to hierarchically ordered structure
复制标题
基于不同长度间隔基“夹套”效应的主链/侧链液晶聚合物自组织：从近晶结构到分级有序结构
DOI：
10.1039/c5ra21257j
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发表时间：
2015
期刊：
影响因子：
3.9
通讯作者：
Chen Er-qiang
中科院分区：
文献类型：
--
作者：
Xie He-lou;Ni Bin;Liu Quan;Wang Jun;Yang Shuang;Zhang Hai-liang;Chen Er-qiang
通过原子转移自由基聚合（ATRP）成功合成了一系列基于“夹套”效应的主链/侧链组合液晶聚合物（MCSCLCP），即具有不同长度烷基间隔基（记为Pn，n代表烷基间隔基中的碳原子数，n = 2-10）的聚{（2，5-双[n-（4-丁氧基-4 '-氧联苯）n-烷基]氧羰基}苯乙烯）。采用联用技术对Pns及其单体的化学结构进行了表征，得到了满意的分析数据。利用差示扫描量热法（DSC）、偏光显微镜（POM）、一维和二维广角X射线衍射（1D和2D WAXD）研究了Pn的相结构和相变。研究表明，P2和P4与短链烷基形成了典型的近晶相。当n ≥ 6时，Pns在低温下表现出类似的分级有序结构，在纳米和亚纳米尺度上具有双重有序性。在该分级结构中，主链基于“夹套”效应形成二维中心矩形支架，支架内的侧链联苯基元堆积成近晶E型结构。矩形点阵的a维随n的增大而增大。当温度升高时，与P6不同，P8和P10呈现相同的相行为，形成侧链的近晶B样堆积，并保持其主链骨架直到各向同性。
A series of combined main-chain/side-chain liquid crystalline polymers (MCSCLCP) based on “jacketing” effect, poly{(2,5-bis[n-(4-butoxy-4′-oxybiphenyl)n-alkyl]oxycarbonyl}styrene) with different lengths of alkyl spacers (denoted as Pn, n represents the number of carbon atoms in the alkyl spacers, n = 2–10) have been successfully synthesized via atom transfer radical polymerization (ATRP). The chemical structures of Pns and the corresponding monomers were characterized using combined techniques with satisfactory analysis data. The phase structures and transitions of Pn were investigated using differential scanning calorimetry (DSC), polarized optical microscope (POM), and one- and two-dimensional wide-angle X-ray diffraction (1D and 2D WAXD). It has been identified that P2 and P4 with short alkyl spacers form typical smectic phase. For n ≥ 6, Pns exhibit similar hierarchical ordered structure at low temperatures, bearing double orderings on the nanometer and sub-nanometer scales. In the hierarchical structure, the main-chains based on “jacketing” effect form a 2D centered rectangular scaffold, and the side-chain biphenyl mesogens within the scaffold pack into a smectic E-like structure. The a dimension of rectangular lattice enlarges with n. When the temperature is increased, different from P6, P8 and P10 present the same phase behavior, forming smectic B-like packing of side chains and maintaining their main-chain scaffold until isotropization.