Page 294 - Book Hosokawa Nanoparticle Technology Handbook

CHAPTER 5 CHARACTERIZATION METHODS FOR NANOSTRUCTURE OF MATERIALS

5.1 Nanostructure and function arrayed parallel on substrates. The next stage of the
nanotechnology will be “programmed assembly” of
(characterization of local nanostructure)
nanomaterials, because this is a foreseeable future tar-
get for the industries of various fields. In the device
The 20th century was the so-called “age of new mate- production by assembling the structured materials,
rial synthesis”, as shown in Fig. 5.1.1 [1]. “Synthesis” “fabrication” is the key technology. Thus, science and
of new substances had been essential to attain a technology for materials is being shifted from “syn-
new property for materials. However, in the recent thesis” toward “processing” and “fabrication”.
R&D of material, keen attention is attracted on Nanobiotechnology has substantial potential for the
controlling material function by the material struc- programmed fabrication of structured materials, in
ture. Nanotechnology is a typical example of this stage which specific interactions between molecules of
of technology. In the control of material structure, DNA or peptide are used to make “hetero-assemblies”
“process” is regarded more important than “synthe- of multi-component materials or nanoblocks (bioma-
sis”. For example, in the nanoparticle production, size terials or bioreactive nanomaterials). Control of
and shape of particle significantly depends on the assembly and disassembly of a variety of biomole-
operating conditions of crystallization process. It was cules, and the nanoblock, will be a key of fabrication
found that some semiconductor materials show strong of multi-component and multistructured materials.
photo-luminescence and the wavelength can be con- Furthermore, if the assembly and disassembly of the
trolled with its particles size (“quantum size effect”). structured materials can be controlled by manipulat-
With a same wavelength of excitation, a wide range of ing the atmosphere, the material will be designed to
colors can be obtained by changing the particle size of change its structure dynamically.
the nanoparticles of CdSe, CdTe, CdS, etc., the so Not only the trend of academic researches men-
called quantum dots (QD) [2]. Photonic crystal can be tioned above but also a significant shift has occurred
produced by self-assembly of nanomaterials (homo- for R&D in chemical industry, in which most of new
assembly) and the control of self-assembly phenomena resources are now devoted to the design and manu-
is a critical issue of process design and operation. In facture of specialty chemicals, structured materials,
the fabrication of ultraviolet (UV) laser [3–5] and and chemical devices rather than traditionally
light-emitting diode (LED) [6] based on ZnO materi- dominant commodity chemicals. Application of the
als, laser molecular beam epitaxy is a powerful process new products covers semiconductors, environmen-
to grow fine ZnO nanocrystals self-assembled and tal, health and medical industries among others.
Determining how to manipulate the properties of
nanomaterials and their size variation has become a
Science and Technology in 21 century worldwide trend in nanotechnology. This has accel-
erated the shift in R&D of new products. Control of
size and shape of nanomaterials and its assembly to
generate structured materials will give rise to create
new products with new functions that will dominate
Performance the new economies.
Nanobiotechnology Devices Nanoanalysis/measurement is very important to
Hetero assembly Fabrication develop “processing” and “fabrication” for nanoma-
of nanomaterials Device structure
terials, because the functions of nanomaterials are
influenced by their size, shape, and structures.
Function
Nanotechnology Characterization methods for analysis and measure-
Materials ment for nanophenomena is essential in the develop-
Homo assembly Processing
of nanoparticles Material structure ment of nanobiotechnology. Especially, development of
precise analysis with atomic level for local nanostruc-
Properties tures such as chemical composition and bonding state,
defects, and impurities, is a key to elucidate the mech-
Substances
Chemical structure Synthesis anism of nanophenomena. Recently, improvements in
analytical equipment have allowed researchers to study
Science and Technology in 20 century and to understand the local nanostructures in functional
materials from atomic level. In this Chapter 5, the top-
Figure 5.1.1 end characterization methods for nanomaterials are
Science and technology in 20th and 21st century. introduced.

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