Physicochemical Soft Matter Research Unit

Principal Investigator

PI Name Fumito Araoka
Degree Ph.D
Title Unit Leader
Brief Resume
2003Ph.D. in Engineering, Tokyo Institute of Technology, Japan
2003Postdoctoral Researcher, Catholic University of Leuven, Belgium
2005Postdoctoral Researcher, The University of Tokyo
2006Postdoctoral Researcher, Tokyo Institute of Technology
2007Assistant Professor, Tokyo Institute of Technology
2013Unit Leader, Physicochemical Soft-Matter Research Unit, Cross-Divisional Materials Research Program, RIKEN Center for Emergent Matter Science (-present)

Outline

Our unit is mainly working on functionality of soft-matter systems from the viewpoints of physical experiments and analyses. In our research unit, particular attention is paid to liquid crystals due to their self-organizability leading to multifarious structures in which many interesting physical phenomena emerge. Our interest also covers potential applications of such soft-matter systems towards optical/electronic or chemical devices. For example, 1. Ferroelectric interactions and switching mechanisms in novel liquid crystalline ferroelectric materials, 2. Chirality related phenomena - origin and control of emergence, as well as applications of superstructure chirality in self-organized soft-matter systems, 3. Novel optical/electronic devices based on self-organized soft-matter systems.

Research Fields

Physical and Structural Properties of Functional Organic Materials

Keywords

Liquid crystals
Polymeric materials
Soft-matter physics
Optical properties
Organic nonlinear optics
Organic ferroelectrics

Results

Large-scale self-organization of reconfigurable topological defect networks in a nematic liquid crystal

Topological defects in continua are ubiquitous. Such topological defects in liquid crystals are important in understanding the fundamental properties of many physical systems, as well as in practical applications, such as colloidal self-assembly, optical vortex generation and templates for molecular self-assembly. Usually, spatially and temporally stable defects require geometrical frustration imposed by surfaces. Otherwise, the system relaxes because of the high cost due to the elastic energy. So far, multiple defects are kept in bulk nematic liquid crystals by top-down approaches. In this work, we succeeded in realizing a network of a large number of ordered topological defects simply by introducing frustrations of anisotropic dielectric/ion-conduction property, and ionic accumulation and vertical alignment properties of perfluoropolymer surface, etc. We also demonstrate optical manipulation of such highly-stabilized topological defect networks.

(A) Materials used in this study, (B) Optical addressing process of the topological defect network, (C) Schematics, (D) Development into a huge topological network of the millimeter-scale.

Members

Fumito Araoka

Unit Leader fumito.araoka[at]riken.jp

Satoshi Aya

Special Postdoctoral Researcher

Jun Yoshioka

Postdoctoral Researcher

Articles

お問い合わせ

2-1 Hirosawa, Wako, Saitama 351-0198 Japan

E-mail:
fumito.araoka[at]riken.jp

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