General phase-structure relationship in polar rod-shaped liquid crystals: Importance of shape anisotropy and dipolar strength. (August 2022)

• Record Type: Journal Article
• Authors: Li, Jinxing; Wang, Zhidong; Deng, Minghui; Zhu, Yuanyuan; Zhang, Xinxin; Xia, Runli; Song, Yaohao; Hisai, Yuki; Aya, Satoshi; Huang, Mingjun
• Is Part Of: Giant. Volume 11(2022)
• Publication Date: 2022-08
• Subjects: Macromolecules -- Periodicals; Nanostructured materials -- Periodicals; Smart materials -- Periodicals; Biomimetic materials -- Periodicals; Nanostructures; Smart Materials; Biomimetic Materials; Macromolecular Substances; Biomimetic materials; Macromolecules; Nanostructured materials; Smart materials; Electronic journals; Periodical; Periodicals; 547.7
• DOI: 10.1016/j.giant.2022.100109
• Languages: English
• ISSNs: 2666-5425

Abstract

Abstract: Ferroelectricity is a property with spontaneous polarization, which is of paramount importance in modern electrooptic applications. Yet, its observations are mostly limited to solids or chiral smectic C liquid crystals with nearly no fluidity. The fluidic ferroelectrics, called ferroelectric nematics, have recently become available by incorporating strong polarity into the apolar liquid crystalline orientational field. Here, we present a rational principle for designing the ferroelectric materials and controlling their phase behaviors. We reveal that, while the apolar nematic order with the second-rank tensor originates from the shape anisotropy in the apolar nematic state, the polarization field serves as an additional mechanism for stabilizing polar nematic orders. Based on a comprehensive set of examinations and machine-learningdriven analyses for about 150 chemically distinct polar rod-shaped molecules, we uncover that the interplay between the shape anisotropy and polarization field gives rise to a diversification of the polar liquid crystal behaviors. The strategy offers much broader design flexibility and may facilitate the development of future polar functional liquid crystals. Graphical abstract: What is the general principle that governs the phase behaviors of polar rod-shaped liquid crystals? To answer this question, we combined molecule library synthesis and machine learning analysis. We established a quadrantal diagram of general phase evolution pathways involving the emerging ferroelectric nematics, and revealed the critical interplay between shape anisotropy and dipolar interaction strength. Image, graphical abstract