Polymer Structure Development in Lyotropic Liquid Crystalline Solutions
Polymer Structure Development in Lyotropic Liquid Crystalline Solutions
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DOI：
10.1021/ma500823q
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发表时间：
2014-08-26
期刊：
影响因子：
5.5
通讯作者：
Guymon, C. Allan
中科院分区：
文献类型：
--
作者：
DePierro, Michael A.;Guymon, C. Allan
在溶致液晶（LLC）介质中的聚合是一种能够合成纳米结构有机聚合物的有前途的方法。为了了解LLC系统中的聚合物结构发展，本研究调查了不同极性和尺寸的丙烯酸酯单体在十二烷基三甲基溴化铵和水的六方和层状相内的聚合。LLC结构，聚合物形态和聚合行为进行了表征，以了解聚合环境和聚合物结构的形成之间的联系。虽然模板相的顺序高度影响最终聚合物的顺序，但单体化学的变化可导致甚至来自相同液晶相的显著不同的聚合物结构。更快的聚合导致相对低分子量单体的更高转化率和更高交联密度，产生高度各向异性的聚合物结构，其显示出延伸长度大于150 μ m的800 nm通道的排列。较不有序的聚合物结构与较高分子量的类似单体一起产生。虽然聚合物结构似乎是由这些系统中的相分离过程产生的，但在几个系统中表现出液晶介质的结构导向影响，包括由聚（乙二醇）二甲基丙烯酸酯在六方相中的聚合形成直径为200 nm的高度取向的圆柱形结构。通过适当选择单体化学、浓度和LLC模板结构，使用LLC模板已经证明了对聚合物结构的显著控制。
Polymerization in lyotropic liquid crystalline (LLC) media is a promising method enabling synthesis of nanostructured organic polymers. To understand polymer structure development in LLC systems, this study investigates the polymerization of acrylate monomers of differing polarity and size within the hexagonal and lamellar phase of dodecyltrimethylammonium bromide and water. LLC structure, polymer morphology, and polymerization behavior were characterized to understand the connection between polymerization environment and formation of polymer structure. While the order of the template phase highly influences final polymer order, variations in monomer chemistry can lead to significantly different polymer structures even from the same liquid crystalline phase. More rapid polymerization, which leads to higher conversion and higher cross-link density of the relatively low molecular weight monomers, yields highly anisotropic polymer structure exhibiting alignment of 800 nm channels extending for lengths greater than 150 mu m. Less ordered polymer structure results with analogous monomers of higher molecular weight. While polymer structure appears to result from a phase separation process in these systems, the structure directing influence of the liquid crystalline media is exhibited in several systems including the formation of highly oriented cylindrical structures with diameter of 200 nm from polymerization of poly(ethylene glycol) dimethacrylate in the hexagonal phase. Significant control of polymer structure has been demonstrated using LLC templates through proper selection of monomer chemistry, concentration, and LLC template structure.