Yamaguchi Masaki, Matsukizono Hiroyuki, Okumura Yasushi, Kikuchi Hirotsugu
Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8580, Fukuoka, Japan.
Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8580, Fukuoka, Japan.
Molecules. 2024 Oct 12;29(20):4837. doi: 10.3390/molecules29204837.
Nanostructured polymer-dispersed liquid crystals (nano-PDLCs) are transparent and optically isotropic materials in which submicron-sized liquid crystal (LC) domains are dispersed within a polymer matrix. Nano-PDLCs can induce birefringence by applying an electric field (-field) based on the reorientation of the LC molecules. If nano-PDLCs are utilized as light-scattering-less birefringence memory materials, it is necessary to suppress the relaxation of the LC molecule orientation after the removal of the -field. We focused on the ferroelectric smectic A (SmA) phase to suppress the relaxation of LC molecules, owing to its layered structure and high viscosity. Although nano-PDLCs require a strong -field to reorient their LC molecules because of the anchoring effect at the LC/polymer interface, the required field strength can be reduced using a ferroelectric smectic A (SmA) LC with a large dielectric constant. In this study, we fabricated a nano-PDLC by shining an ultraviolet light on a mixture comprised an SmA LC, photocurable monomers, and a photo-initiator. The electro-birefringence effect was evaluated using polarizing optical microscopy. After the removal of the -field, an enhanced memory effect was observed in the sample using SmA LC compared with nematic LC-based nano-PDLCs.
纳米结构聚合物分散液晶（nano-PDLCs）是一种透明且光学各向同性的材料，其中亚微米尺寸的液晶（LC）畴分散在聚合物基质中。基于LC分子的重新取向，nano-PDLCs可以通过施加电场来诱导双折射。如果将nano-PDLCs用作无散射双折射存储材料，则有必要抑制去除电场后LC分子取向的弛豫。由于其层状结构和高粘度，我们聚焦于铁电近晶A（SmA）相来抑制LC分子的弛豫。尽管由于LC/聚合物界面处的锚定效应，nano-PDLCs需要强电场来重新取向其LC分子，但使用具有大介电常数的铁电近晶A（SmA）LC可以降低所需的场强。在本研究中，我们通过对由SmA LC、光固化单体和光引发剂组成的混合物照射紫外光来制备nano-PDLC。使用偏光光学显微镜评估电双折射效应。去除电场后，与基于向列相LC的nano-PDLCs相比，使用SmA LC的样品中观察到增强的记忆效应。
