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Introduction to polymer networks

Published on 27 February 2024. Downloaded on 2/28/2024 9:34:24 AM.

Cite this: DOI: 10.1039/d4sm90027h

Yukikazu Takeoka

DOI: 10.1039/d4sm90027h
rsc.li/soft-matter-journal

Gels and elastomers composed of polymer
networks have been studied in various basic
and applied fields, and materials with various functions useful for daily life have beendeveloped. One of the reasons for this progress in the research may be the ease withwhich researchers in various fields havebeen able to prepare similar materials.
Furthermore, along with the development of precise synthesis methods inorganic chemistry, the development ofvarious nanomaterials that can be usedas building blocks in inorganic chemistry,
and the challenge of unknown areas inbiochemistry, the study of gels and elastomers has made increasingly significant
progress over the past two decades. For
example, gels, which were once recognized
as mechanically brittle, have become very
tough materials, even when they hold a lotof solvent. As a result, they are being used
as artificial organs. It had been believedthat the restorative force of a deformed gel
can be roughly explained by the entropic
elasticity derived from the deformation of

the polymer chains. However, it was foundthat the restorative force of gels is notdetermined by entropy elasticity alone,
but is greatly weakened by ‘‘negative
energy elasticity’’ derived from the solvent.
This finding demonstrates that the ‘‘temperature dependence of softness,’’ which
is important for the use of gels in food andmedical applications, can be several times
greater than previously assumed. In elastomers as well, advances in analyticalmethods and simulations have led to abetter understanding of toughening byadding fillers to cross-linked networks,
and the development of more highly functional rubber materials.
To keep abreast of these remarkabledevelopments in gels and elastomers, weorganized the Gel Symposium 2022 (https://www.gelsymposium2022.com), a traditional
international conference on polymer gels, inTomamu, Hokkaido, Japan. At that time, wecould not invite many foreign speakers
because of the coronavirus disaster, but weinvited prominent foreign researchers togive lectures online. One of the invited
speakers at that time, Professor Alfred
Crosby of the University of Massachusetts
Amherst in the U.S., cooperated to publish
this themed issue in Soft Matter and Polymer
Chemistry. In this joint themed issue, 1Review, 29 Papers, and 2 Communications
were published in Soft Mater, and 9 Papers
and 2 Communications were published inPolymer Chemistry. All of the papers werevery interesting and contained the latest
information, making this a very readable
themed issue.
The Gel Symposium will be held again
this November in Okinawa, an island in
the south of Japan, by the members whoparticipated in this themed issue as guest
editors. The Gel Symposium 2024 (https://gelsymposium.com and https://gelsymposium.studio.site/) will feature 101 invited
speakers, including 26 authors of thisjoint themed issue, who will present theirlatest research. If you are interested in thelatest trends in current polymer gels andelastomers, please come to Okinawa.

Nagoya University, Japan. E-mail: ytakeoka1@mac.com

This journal is © The Royal Society of Chemistry 2024

Soft Matter