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NanoMat 2018
Nano Research & Applications
ISSN: 2471-9838
Page 29
April 26-27, 2018
Rome, Italy
17
th
Edition of International Conference on
Emerging Trends in
Materials Science and
Nanotechnology
S
ize and size distribution are significant physicochemical
properties of bio and functional materials since it
determines many of the functional properties of these
materials. Methods for the accurate determination of the size
and the size distribution of materials are therefore one of the
key to the development of nano and biotechnologies. In the
past few decades, dynamic light scattering (DLS) and particle
tracking analysis (PTA) have been widely used for determining
the sizes of Brownian nanoparticles in nano and submicron
scale biocolloidal suspensions. Because of the convenience
and usability of DLS, a large number of commercial instruments
and analytical methods based on various principles underlying
the DLS method are available. In DLS and PTA analysis,
the diffusion coefficients of nanomaterials are determined
first, after which the averaged diameters of the particles are
calculated from the diffusion coefficients by using the Stokes–
Einstein relationship. However, the apparent diameters of
nanoparticles over a wide size distribution as determined
using such diffusion based analysis method depends on
the particular analytical algorism. Electron microscope is an
effective method to obtain the primary particle information
visually, however; it requires counting a large number of
materials for ensemble characterization. Additionally, the
European Commission has declared that a nanomaterial is
a natural, incidental or manufactured material containing
particles, in an unbound state or as an aggregate or as an
agglomerate and where, for 50% or more of the particles in the
number size distribution, one or more external dimensions is
in the size range 1 nm–100 nm. According to this definition,
not only the size but also the size distribution of nanomaterials
in is an important factor for nanomaterial industrial field.
Fractionation methods such as field-flow fractionation (FFF)
and microfluidic/nanofluidic technological separation have
recently been focused upon as methods for the determination
of accurate size distribution. FFF is elution techniques
wherein nanoparticles, microparticles, and macromolecules
are separated by their physicochemical properties. In nano
and micro technology, various FFF methods are attractive
techniques for separating materials in colloidal dispersions by
means of flow, centrifugal, magnetic, and thermal field control.
Different fields enable nanoparticle separation based on
various criteria: diffusion coefficient (i.e. hydrodynamic size)
by flow FFF, thermal diffusion coefficient, density, mass, and
so forth. The most general applicable FFF methods are flow
FFF and centrifugal FFF because of their practicality and the
robust theoretical foundation established for separation of
nano and micro materials in many areas. Herein, we performed
FFF assessments of various materials combined with DLS
and EM methods to characterize more accurate size and
size distribution of materials than the results by single sizing
method such as DLS. This study plays an important role in
producing a new application of nano and biotechnology.
Recent Publications
1. H Kato, et al. (2018) Separation of different-sized
silica nanoparticles using asymmetric flow field-flow
fractionation by control of the Debye length of the
particles with the addition of electrolyte molecules.
Colloids and Surfaces A: Physicochemical and
Engineering Aspects 538:678-685.
2. H Kato, et al. (2017) Simultaneous measurement
of size and density of spherical particles using two-
dimensional particle tracking analysis method.
Powder Technology 315:68-72.
3. Y Matsuura, et al. (2017) Accurate size determination
of polystyrene latex nanoparticles in aqueous media
using a particle tracking analysis method. Colloids
and Surfaces A: Physicochemical and Engineering
Aspects 525:7-12.
4. H Kato, et al. (2017) Determination of bimodal size
distribution using dynamic light scattering methods
in the submicrometer size range. Material Express
6:175-182.
5. H Kato,
et.al(2014) Separation of nano and micro
sized materials by hyphenated flow and centrifugal
field-flow fractionation. Analytical Methods 6:3215-
3218.
Characterization of nanomaterials using field-flow fractionation
Haruhisa Kato
National Metrology Institute of Japan - AIST, Japan
Haruhisa Kato, Nano Res Appl, Volume:4
DOI: 10.21767/2471-9838-C1-008