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Photonic water dynamically responsive to external stimuli.
Koki Sano1,2, Youn Soo Kim1, Yasuhiro Ishida2
1Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Nature Communications
|August 31, 2016
Summary
This study introduces "photonic water," a fluid with ordered nanostructures that displays tunable structural colors. This novel material, made from titanate nanosheets, can change color in response to stimuli.
Area of Science:
- Materials Science
- Nanotechnology
- Photonics
Background:
- Ordered nanostructures can produce structural colors tunable by external stimuli, similar to color changes in some fish.
- Titanate nanosheets are negatively charged nanoparticles with potential for self-assembly.
Purpose of the Study:
- To investigate the structural color properties of a dilute aqueous colloidal dispersion of titanate nanosheets.
- To explore the tunability of structural colors in this 'photonic water' system.
Main Methods:
- Preparation of a dilute aqueous colloidal dispersion of negatively charged titanate nanosheets.
- Characterization of the nanostructure ordering and optical properties.
- Application of external stimuli (magnetic flux, physical/chemical changes) to modulate color.
Main Results:
- The titanate nanosheets spontaneously formed a cofacial geometry with ultralong periodic distances (up to 675 nm) due to electrostatic repulsion.
- The resulting 'photonic water' exhibited structural colors and reflected near-infrared light up to 1,750 nm.
- Structural color vividness increased under magnetic flux, inducing monodomain ordering.
- Reflective color was tunable across the visible spectrum via external stimuli.
Conclusions:
- A novel photonic fluid ('photonic water') based on titanate nanosheets was developed, exhibiting tunable structural colors.
- The system demonstrates potential for applications requiring dynamic color modulation.
- Electrostatic repulsion and external stimuli are key factors in controlling the optical properties of this nanomaterial dispersion.
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