Department of Chemistry and Chemical Engineering, School of Chemistry and Biological Engineering , University of Science and Technology Beijing , Beijing 100083 , People's Republic of China.
Department of Materials Science and Engineering, College of Engineering , Peking University , Beijing 100871 , People's Republic of China.
ACS Appl Mater Interfaces. 2018 Jul 5;10(26):22757-22766. doi: 10.1021/acsami.8b06324. Epub 2018 Jun 25.
In this work, a bistable polymer framework liquid crystal (PFLC) thin film by thermal curing of epoxy monomers with two different thiols, a traditional flexible-structure thiol and a novel original rigid-structure thiol, has been successfully fabricated, combining a novel mixed morphology of polymer matrix and cholesteric liquid crystals with negative dielectric anisotropy. The polymer framework morphology has been formed by curing two types of epoxy monomers with two types of thiols, and the liquid crystals tend to be focal conic textures with large size domains at the initial state in the PFLC film so that it has a moderate light transmissivity at this state between the transparent state and the opaque state. Thus, the devices based on PFLC films can be switched reversibly between the transparent state and the opaque state by alternative electric field. In addition, the states can be sustained after the electric field is removed. The bistable memory effect comes from the anchoring effects of the polymer frameworks with a novel morphology in the microdomains of the PFLCs. Therefore, the optimized bistable PFLC film keeps its initial state without external electric field and any other energy consumption for a long time after altering the state by applying an instant electric field. The special polymer frameworks in the bistable PFLC films endow the films with excellent electro-optical properties and mechanical properties. The devices are energy-efficient and cost-saving and have great potential applications in energy-efficient reflective displays, electronic papers, writing tablets, and smart windows.
在这项工作中，通过热固化两种不同硫醇的环氧树脂单体，成功制备了一种双稳态聚合物框架液晶（PFLC）薄膜，这两种硫醇分别为传统的柔性结构硫醇和新型原始刚性结构硫醇，结合了具有负介电各向异性的聚合物基质和胆甾相液晶的新型混合形态。聚合物框架形态是通过两种类型的硫醇固化两种类型的环氧树脂单体形成的，在 PFLC 薄膜的初始状态下，液晶倾向于形成大尺寸畴的焦锥织构，因此在透明状态和不透明状态之间具有适度的光透过率。因此，基于 PFLC 薄膜的器件可以通过交替电场在透明状态和不透明状态之间可逆切换。此外，在去除电场后，状态可以保持。双稳态记忆效应来自于 PFLC 微区中具有新型形态的聚合物框架的锚定效应。因此，优化后的双稳态 PFLC 薄膜在通过施加瞬时电场改变状态后，无需外部电场和任何其他能量消耗即可长时间保持其初始状态。双稳态 PFLC 薄膜中的特殊聚合物框架赋予了薄膜优异的电光性能和机械性能。这些器件具有节能和节省成本的特点，在节能反射式显示器、电子纸、写字板和智能窗户等方面具有巨大的应用潜力。
