Thermodynamic analysis of reaction-induced phase separation in epoxy-based polymer dispersed liquid crystals (PDLC)
Thermodynamic analysis of reaction-induced phase separation in epoxy-based polymer dispersed liquid crystals (PDLC)
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DOI：
10.1016/s0032-3861(97)00276-0
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发表时间：
1998-02-01
期刊：
影响因子：
4.6
通讯作者：
Pascault, JP
中科院分区：
文献类型：
--
作者：
Borrajo, J;Riccardi, CC;Pascault, JP
弗洛里-哈金斯的各向同性相混合自由能理论，结合Maier-Saupe的向列相液晶相变理论，应用于凝胶前和凝胶后阶段的二氧化二胺-液晶混合物。在进行分析时，考虑到在任何转化水平上聚合物种类的分布。在凝胶后阶段，弹性能的贡献被包含在自由能表达式中。在覆盖整个转换范围的温度-成分坐标下，生成了具有各向同性-各向同性和向列-各向同性平衡特征的云漆曲线和阴影曲线。数值模拟可以再现各向同性向列跃迁的实验结果，其中相互作用参数与温度成反比，随转换而减小。热力学分析可以用来控制聚合物分散液晶的形态。1997爱思唯尔科学有限公司
The Flory-Huggins theory for the free energy of mixing in isotropic phases, in conjunction with the Maier-Saupe theory for phase transition of a nematic liquid crystal, was applied to a diepoxide-diamine-liquid crystal blend in pre-and post-gel stages. The analysis was performed taking the distribution of polymeric species into account at any conversion level. In the post-gel stage, the elastic energy contribution was included in the free energy expression. Cloud-paint and shadow curves, characteristic of isotropic-isotropic and nematic-isotropic equilibria, were generated in temperature versus composition coordinates covering the whole conversion range. Experimental results for the isotropic-nematic transition could be reproduced by numerical simulation, using an interaction parameter inversely proportional to temperature and decreasing with conversion. The thermodynamic analysis can be used to control the morphologies of polymer dispersed liquid crystals. (C) 1997 Elsevier Science Ltd.