Dynamical heterogeneity and critical Casimir effect

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K18740
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 13:Condensed matter physics and related fields
• Research Institution: Ritsumeikan University
• Principal Investigator: Fukao Koji 立命館大学, 理工学部, 教授 (50189908)
• Project Period (FY): 2018-06-29 – 2021-03-31
• Keywords: カシミール力 / 動的不均一性 / 液晶滴 / 欠陥構造 / 回転運動

Outline of Final Research Achievements

At the beginning the purpose of this study was to elucidate the correlation between the critical Casimir force applied to colloid particles in the critical concentration of the polymer blends and the dynamical heterogeneity of glass dynamics. However, the research done in the first period of this project clarified the difficulty in detecting the tiny Casimir force applied to colloid particles via laser tweezer. Hence, we have changed our target from colloid particles to liquid crystal droplets and we obtained the following two results: 1) For Cholesteric liquid crystal droplets, the competition between isotropic elasticity and molecular orientation at the interface can induce the various types of defect structure. The stability of the defect structure has been successfully elucidated. 2) From the analysis of structural change under temperature gradient to liquid crystal droplets with point defects, we could observe the twist and rotational motion of the internal director field.

Free Research Field

ソフトマター物理学

Academic Significance and Societal Importance of the Research Achievements

当初想定した結果には到達していないが、液晶滴に対して得られた結果は、アクティブマターの特徴を理解するために不可欠なものである。アクティブマターは私たちの生活に密接に関わっている物質群を構成し、またこれまでに未解明の非線形・非平衡に関連した基礎的な物理現象をもたらすものとも言える。したがって、本研究のこれまでの結果は、私たちの生活に直接関わる科学に大きく貢献する可能性があり、学術的・社会的に十分な意義を有する。