490 Book Reviews

and the ways in which this structure may be bonded: the gel is neither liquid nor solid but, conversely, is both. It is a spec- tacular form of soft matter, which responds to very small external forces. Gels will swell or contract under very small changes in some parameters-hange of pH, addition of ions, change of type of solvent (although the world of aqueous- based gels is also most of the World of Living Nature). Gels tend to be elastically soft and osmotically active: this duality confers their special absorptive and rheological properties, which are the basis of many applications.

In five chapters (and a Foreword by Professor P. G. de Gennes, the most recent Nobel Laureate in Polymer Science, who mentions the 1995 Faraday Discussion in Paris, on Polymer Gels) a group of French and German authors (including the editor himself) deal mainly with experimental methods introduced to study both reversible and irreversible gels: the methods include neutron scattering, NMR and quasi- elastic light scattering; the gel behaviour studied includes semi-dilute solutions (which may be considered as weak- structure gels), polyelectrolyte gels, sol-gel transitions, micro- scopic structure of well-formed networks, and the swelling or stretching effects which indicate structural aspects specific to neutral as well as charged polymeric gels.

There are many yet-unsolved aspects of the study of the complexities of polymeric gels-this volume, dealing with both experimental results and theoretical concepts, provides some of the answers, and leads to the consideration of many more problems.

C. A. Finch

Flow-induced structure in polymers ACS symposium series no. 597 Edited by Alan I. Nakatani and Mark D. Dadmun. American Chemical Society, Washington DC, 1995. pp. xii + 364, price US99.95.

It is perhaps unusual to review a book in which one appears as an author! However, this volume contains a set of 23 art- icles developed around the presentations at the 1994 Amer- ican Chemical Society Symposium with the same title. The author’s contribution is therefore less than 5% of the whole and can be rapidly passed over! The field represented-the interaction of rheology, through flow, with the organization and structure of polymeric materials-is a very rapidly developing one. The symposium attracted widespread interna- tional participation and most of the ‘big players’ in the field were represented. The volume therefore provides a ‘snapshot’ of the recent experimental results and theoretical develop- ments and is a key item for the book shelves in libraries and laboratories. The areas covered fall into five sections: solu- tions, melts of one or more components, block copolymers and liquid crystal polymers. The results reported are almost all recent research findings, and the papers are multi- authored. It is therefore not possible to include a list of authors here. Suffice to say that work is presented from Japan, France, Italy, the United Kingdom, Germany, Denmark, Taiwan, Russia, and of course the USA; rheological measure- ments and flow birefringence as well as light and neutron scat- tering data are presented, and often compared for a variety of systems, and theoretical explanation is not neglected. For a few years at least this will serve as a very useful introduction to ‘who’s who’ and ‘who’s doing what’ in this rapidly expand- ing, technologically important and intellectually demanding field.

ISBN 0-8412-3230-X

J. S. Higgins

POLYMER INTERNATIONAL VOL. 41, NO. 4, 1996