A
polymer gel is a cross-linked three
dimentional polymer networks that contains liquids in its internal
space. It is a soft matter intermediate between a solid and a liquid.
The gel shows discontinuous volume change when a external stimuli such
as temperature, light and electric field, is imposed upon it. It is
called a stimuli responsiveness.
The polymer gel swells or shrinks when
external condition such as ion strength or solvent composition is
changed. It is called a phase transition. The phase transition in gels
caused by four fundamental interactions, i.e. hydrogen bonding,
hydrophobic interaction, van der Waals interaction and ionic
interaction between ionized groups.
There are many potential applications of the polymer
gels such as the separation of solutes or metal ions,
immobilization of enzymes and drug delivery system. New application
also has been developed, in which gel networks are used as a reaction,
separation and/or chemo-mechanical energy transformation media, for
example, adsorbents, membranes, chromatography and preparation of fine
particles in the gel networks.
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Department of Chemical Engineering
Graduate School of Engineering
Hiroshima University
1-4-1, Kagamiyama, Higashi-Hiroshima 739-8527,
Japan