Download Presentation Title Nanosheet Liquid Crystals : Macroscopically

Presentation Title
Nanosheet Liquid Crystals : Macroscopically Ordered Colloidal Structures
Constructed by Inorganic Nanocrystals
Speaker
Teruyuki Nakato
Affiliation
Department of Applied Chemistry, Kyushu Institute of
Technology, 1-1 Sensui-cho, Tobata-ku, Kitakyushu-shi,
Fukuoka 804-8550, Japan
TEL&FAX : +81-0093-884-3308
E-mail: [email protected]
Professional Career
1987-1992
Undergraduate & Graduate Research, Waseda University (Profs. C.
Kato and K. Kuroda)
1991-1993
Research Associate, Waseda University
1993-1999
Research Associate, Hokkaido University
1999-2011
Associate Professor, Tokyo University of Agriculture and
Technology
2011-present
Professor, Kyushu Institute of Technology
Academic Background
1992 Ph.D, Graduate School of Sci. & Eng., Waseda University
1989 M. Eng, Graduate School of Sci. & Eng., Waseda University
1987 B. Eng, Dept. of Applied Chemistry, Waseda University
Academic Activity
The Chemical Society of Japan,
Forum of Low-Dimensional Photofunctional Materials, CSJ,
The Clay Science Society of Japan,
The Society of Polymer Science, Japan,
The Ceramic Society of Japan
Research Project
Organization of Photofunctional Inorganic-Organic Fusion Liquid Crystals
Abstract:
Colloidal liquid crystals (LCs) of inorganic particles are very rare examples
of inorganic soft structures.1 They are lyotropic systems that exhibit ordered
structures of anisotropic particles like rods and plates at high particle
concentrations. The LC phase is entropically driven based on the particles’
excluded volume effect. In the inorganic colloidal LCs, crystalline inorganic
particles are mobile but ordered. Versatile properties of inorganic crystals
such as semiconducting, dielectric, and (photo)catalytic functions, can be
utilized in such materials.
Colloidal LCs of inorganic nanosheets, called nanosheet LCs, are typical
examples of such systems. They are constructed by extremely thin 2D
particles obtained by exfoliation of inorganic layered crystals in solvents.
The nanosheet LCs are characterized by m-size mesogens with high
anisotropy ensured by their thickness of around 1 nm. They are
distinguished from conventional organic molecular LCs because of the
mesogen size being much larger than that of
External forces
~ 2 µm
molecules and the crystallinity of the
Nanosheet
mesogens.
The size and robustness of the crystalline
mesogens of the nanosheet LCs allow
multiscale organization of hierarchical
structures controlled over all length-scale
LC domain
> Sub-mm
from micro-, meso-, to macroscopic, which is
Multiscale structure
impossible with the conventional organic
LCs.2 The nanosheets have rich
Figure 1. Schematic representation of a
alternatives of arrangements for higher-order multiscale structure hierarchically
organized by a nanosheet LC, in which the
structures compared with 1D rods, because
LC domains constructed by assembly of
the mesogenic inorganic nanosheets work
2D particles have two different axes for
as the secondary building blocks.
regulation of their alignment. In fact,
hierarchically structured arrays of nanosheet LCs are obtained with careful
orientational control of the nanosheets. Two-stage manipulation of the LCs
involving controlled LC domain growth and application of dual external forces
generates the multiscale structures that are characterized by sub-mm to mm
length scales (Figure 1).
References:
1 N. Miyamoto, T. Nakato, Isr. J. Chem. 2012, 52, 881, and references
therein.
2
T. Nakato, Y. Nono, E. Mouri, M. Nakata, Phys. Chem. Chem. Phys.
2014, 16, 955.
Selected Publications
1. Nakato, T., Watanabe, S., Fujita, T., Mouri, E.
“Effects of Clay-Water Interface on the Photoindued Electron Transfer from
Ruthenium-bipyridyl Complex to Methylviologen”,
Clay Sci., 17, 23-29 (2013).
2. Nakato, T., Ueda, H., Hashimoto, S., Terao, R., Kameyama, M., Mouri, E.
“Pickering Emulsions Prepared by Layered Niobate K4 Nb6 O17 Intercalated with
Organic Cations and Photocatalytic Dye Decomposition in the Emulsions”,
ACS Appl. Mater. Interfaces, 4, 4338-4347 (2012).
3. Nakato, T., Watanabe, S., Kamijo, Y., Nono, Y.,
“Photoinduced Electron Transfer between Ruthenium-Bipyridyl Complex and
Methylviologen in Suspensions of Smectite Clays”,
J. Phys. Chem. C, 116, 8652-8660 (2012).
4. Nakato, T., Kasai, T.
“Preparation of Au-Loaded Niobate Nanosheets and Their Plasmon-Driven
Photochemical Reaction”,
Mater. Lett., 65, 3402-3404 (2011).
5. Nakato, T., Nakamura, K., Shimada, Y., Shido, Y., Houryu, T., Iimura, Y.,
Miyata, H.
“Electrooptic Response of Colloidal Liquid Crystals of Inorganic Oxide
Nanosheets Prepared by Exfoliation of a Layered Niobate”,
J. Phys. Chem. C, 115, 8934-8939 (2011).