Orientation state in drying process of thin liquid film of rod-like molecules/particles suspension oriented by application process

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H02064
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 19010:Fluid engineering-related
• Research Institution: Nagaoka University of Technology
• Principal Investigator: Takahashi Tsutomu 長岡技術科学大学, 工学研究科, 教授 (20216732)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 塗布 / 乾燥 / 複屈折 / 流動配向 / 液晶 / 粒子分散系流体

Outline of Final Research Achievements

We investigated methods for quantitative evaluation of changes in the orientation of particles and molecules during the drying process of coated films and for visualization of changes in the two-dimensional distribution of volume fractions during the drying process, with a view to practical application of technology for forming high-performance and high-performance thin films such as optically anisotropic films and electrodes for secondary batteries by coating. The two-dimensional distribution of birefringence induced by orientation was visualized by a high-speed polarized light imaging camera during the drying process of coated films of solutions and suspensions containing rod-shaped molecules and particles, and the transient changes during the drying process were clarified. For nanoparticle dispersion fluid films, we developed a technique to evaluate the temporal change in volume fraction as an image, and clarified the process of crack initiation during the drying process.

Free Research Field

流体力学

Academic Significance and Societal Importance of the Research Achievements

二次電池や高機能光学フィルムの高性能化と高機能化を行い，かつ安価に安定して大量生産を可能とする手法として機能性を有する微粒子や分子を含む溶液を精密塗布し，分子配向膜を形成する技術が求められている．本研究ではこれまで困難であった塗布後の液膜の乾燥過程における分子の配向状態や体積分率の時間的・空間的な変化を画像（動画）により明確に定量化できる技術を提案したもので，コーティング，塗装，高機能薄膜形成など様々な産業分野に対して重要な情報を与える実験手法となる．体積分率分布の評価方法はケンブリッジ大学・ラウス教授のアドバイスを含めて共著で国際誌に掲載され，学術的にも高評価を得た．