Moon Jihyeon, Seo Kyutae, Kang Hyo
BK-21 Four Graduate Program, Department of Chemical Engineering, Dong-A University, 37 Nakdong Daero 550beon-gil, Saha-gu, Busan 604-714, Korea.
Polymers (Basel). 2021 Mar 7;13(5):819. doi: 10.3390/polym13050819.
This study demonstrates liquid crystal (LC) alignment behaviors on the surface of phytochemical-based and renewable chavicol-modified polystyrene (PCHA#, # = 20, 40, 60, 80, and 100, where # represent the molar content of chavicol moiety in the side group) via polymer modification reactions. Generally, a LC cell fabricated with a polymer film containing a high molar content of the chavicol side group exhibited a vertical LC alignment property. There is a correlation between the vertical alignment of LC molecules and the polar surface energy value of the polymer films. Therefore, vertical LC alignment was observed when the polar surface energy values of these polymer films were smaller than about 1.3 mJ/m, induced by the nonpolar chavicol moiety having long and bulky carbon groups. Aligning stability under harsh conditions such as ultraviolet (UV) irradiation of about 5 J/cm was observed in the LC cells fabricated from PCHA100 film. Therefore, it was found that the plant-based chavicol-substituted polymer system can produce an eco-friendly and sustainable LC alignment layer for next-generation applications.
本研究通过聚合物改性反应，展示了基于植物化学物质且可再生的丁香酚改性聚苯乙烯（PCHA#，# = 20、40、60、80和100，其中#代表侧基中丁香酚部分的摩尔含量）表面的液晶（LC）取向行为。一般来说，用含有高摩尔含量丁香酚侧基的聚合物薄膜制成的LC盒表现出垂直的LC取向特性。LC分子的垂直取向与聚合物薄膜的极性表面能值之间存在相关性。因此，当这些聚合物薄膜的极性表面能值小于约1.3 mJ/m²时，由具有长且庞大碳基团的非极性丁香酚部分诱导，观察到垂直的LC取向。在由PCHA100薄膜制成的LC盒中，观察到在约5 J/cm²的紫外线（UV）照射等苛刻条件下的取向稳定性。因此，发现基于植物的丁香酚取代聚合物体系可为下一代应用生产环保且可持续的LC取向层。
