Liquid crystal microspheres with high tunability of selective reflection properties by light and electric-field

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K05624
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 35030:Organic functional materials-related
• Research Institution: Utsunomiya University (2022); Hokkaido University (2019-2021)
• Principal Investigator: Kim Yuna 宇都宮大学, 工学部, 助教 (00648131)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 液晶 / マイクロ球体 / 光異性化 / エレクトロクロミズム / デバイス

Outline of Final Research Achievements

Cholesteric liquid crystals (CLC) incorporating sugar-containing macrocyclic azobenzene derivatives as photoresponsive chiral additives exhibited optical modulation properties of helical pitch length up to 500%. Microspheres with CLC in the core or polythiophene derivatives in the shell were fabricated using a microfluidic device. The spheres showed reversible control of reflected lights (blue-green ⇔ yellow ⇔ red) by irradiation with ultraviolet and visible light, and the rapid response property of coloring and bleaching in 2~3 seconds was obtained when an electric field was applied to the device. On the other hand, by introducing a complex of an ionic liquid and a luminescent europium complex into a electrochemical switching device, controlling the redox reaction of the complex with an electric field enabled the switching of the red emission intensity.

Free Research Field

有機機能性材料化学

Academic Significance and Societal Importance of the Research Achievements

本研究で開発した複合マイクロ球体材料やデバイスは、全方位にわたる選択反射光の波長・強度や吸収度を、光と電場により多段階で制御できるため、全方位反射型ディスプレイ、レーザー共振器等の開発につながると確信している。また、透明なイオン液体複合体をCLC球体デバイスに導入することで、今後光・電場に応答する反射光・発光の多重スイッチングを可能とする光学デバイス分野へ大きな波及効果を与えると期待できる。