Thermoresponsive mobility of liquid crystals and reactive mesogens during photopolymerization-induced phase separation
Thermoresponsive mobility of liquid crystals and reactive mesogens during photopolymerization-induced phase separation
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光聚合诱导相分离过程中液晶和反应性介晶的热响应迁移率
DOI：
10.1103/physreve.106.044704
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发表时间：
2022
影响因子：
2.4
通讯作者：
and Akifumi Ogiwara
中科院分区：
文献类型：
--
作者：
Hiroshi Kakiuchida;Akihiko Matsuyama;Eiichi Kobayashi;and Akifumi Ogiwara
在光聚合诱导相分离（PPIPS）过程中，从原始混合物开始，直到形成聚合物网络液晶（PNLCs），全面研究了液晶（lc）与反应性介原（rm）在温度下跨相变区域的分子相互作用。然后，发现随着PPIPS的进展，分子对温度的响应是非均匀的或多或少的流动性。以4-氰基-4′-己基联苯（6CB）和1,4双-[4-（3-丙烯酰氧基丙基）苯甲酰氧基]-2-甲苯（RM257）作为典型的LCs和RMs，仔细测量了PPIPS的光学双折射和红外吸收。获得了lc和RMs分子取向顺序热响应变化的微观视图：原料混合物中的lc和RMs相互作用，但均匀地改变其分子取向。随着PPIPS的发展，这种相互作用不断变化，变得不均匀。在PPIPS的初始阶段，RMs（聚合但未完全联网）抑制LCs改变其分子取向，反之亦然。随着PPIPS的发展，由于RM的限制，一些LCs变得更灵活，而一些LCs变得更不灵活。亚微米相分离的畴结构影响了lc和RMs的热响应迁移率，即lc在lc丰富的区域变得更容易迁移。这里的定量知识提供了全面的见解，即LCs和rm是相互约束的，并且这种交互行为随着PPIPS的进展而不均匀地变化。
Molecular interactions between liquid crystals (LCs) and reactive mesogens (RMs) at temperatures across the phase transition regions were comprehensively studied during photopolymerization-induced phase separation (PPIPS) beginning with raw mixtures until the formation of polymer network liquid crystals (PNLCs). Then, the molecules were found to be nonuniformly more and less mobile in response to temperature as PPIPS progressed. Optical birefringence and infrared absorption were carefully measured throughout PPIPS, using 4-cyano-4′-hexylbiphenyl (6CB) and 1,4bis-[4-(3-acryloyloxypropyloxy) benzoyloxy]-2-methylbenzene (RM257) as typical LCs and RMs. Microscopic views of thermoresponsive changes in the molecular orientation order of both LCs and RMs were obtained: LCs and RMs in raw mixtures interacted with one another but uniformly transformed their molecular orientation. Such interactions continuously change to become nonuniform with progress in PPIPS. At the incipient stages of PPIPS, RMs, which are polymerized but not completely networked, inhibit LCs from changing their molecular orientation and vice versa. As PPIPS progresses, some LCs become more mobile and some less mobile owing to RM constraints. The domain configuration of the submicrometer phase separation affects the thermoresponsive mobility of LCs and RMs, that is, LCs become more mobile in LC-richer areas. The quantitative knowledge here provides comprehensive insight that LCs and RMs are mutually constrained and that such interactive behavior varies nonuniformly as PPIPS progresses.