|
Summary of Research Projects (Supports in 2004
Fiscal Year)
| Subjects |
Phase Behavior of Colloidal Systems Consisted of Small
Numbers of Particles Examined by Gel Immobilization Method |
| Representative researcher |
Graduated school of Pharmaceutical Sciences,Nagoya City University
Junpei YAMANAKA |
| Colloidal systems have attracted
considerable attention as a model condensed matter to study
phase behavior of atomic and molecular systems in general.
Thus far, however, most of the studies focused on the bulk
colloidal system, which consisted of large numbers of particles.
As seen in ultra-fine particles, systems including small numbers
of constituents exhibit peculiar properties, e.g., significantly
lower melting temperature than that for the bulk system. As
a model for such system with small numbers of constituents,
here we constructed microscopic colloidal dispersions consisted
of ~100 to ~1000 particles, by confining them in giant liposome
(GL) having diameters of about 10 - 150 μm.
They were obtained by preparing the GL from cast film of lecithin
in aqueous dispersion of the polystyrene particles, and by
immobilizing the GL in polymer hydrogel matrix. The crystallization
behavior of the confined colloid was examined by applying confocal
laser scanning microscopy and phase contrast microscopy. We
studied two types of crystallization, that is, formations of
opal crystals due to sedimentation of the particles, and charge-stabilized
crystals. In both cases the crystallization was more suppressed
for smaller GL, in other words, for systems containing smaller
numbers of particles. |
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