Water A Comprehensive Treatise

This Volume, the last of the series, is devoted to water in its metastable forms, especially at sub-zero temperatures. The past few years have wit nessed an increasing interest in supercooled water and amorphous ice. If the properties of liquid water in the normal temperature range are already eccentric, then they become exceedingly so below the normal freezing point, in the metastable temperature range. Water can be supercooled to -39°C without too much effort, and most of its physical properties show a re markable temperature dependence under these conditions. Although ade quate explanations are still lacking, the time has come to review available knowledge. The study of amorphous ice, that is, the solid formed when water vapor is condensed on a very cold surface, is of longer standing. It has achieved renewed interest because it may serve as a model for the liquid state. There is currently a debate whether or not a close structural relation ship exists between amorphous ice and supercooled water. The nucleation and growth of ice in supercooled water and aqueous solutions is also still one of those grey areas of research, although these topics have received considerable attention from chemists and physicists over the past two decades. Even now, the relationships between degree of supercooling, nucleation kinetics, crystal growth kinetics, cooling rate and solute concentration are somewhat obscure. Nevertheless, at the empirical level much progress has been made, because these topics are of considerable importance to biologists, technologists, atmospheric physicists and gla ciologists.

Since the publication of the previous volumes many new aspects of the physical and life sciences have been developed in which the properties of water play a dominant role. Although, according to its preface, Volume 5 was to be the last one of the treatise, these recent developments have led to a revision of that statement. The present volume and its companion, still in preparation, deal with topics that were already mentioned in the preface to Volume 5 as gaining in importance. The recent development of X-ray and, more particularly, neutron scattering techniques have led to studies of "structure" in aqueous solutions of electrolytes on the one hand, and to the role of water in protein structure and function on the other. Both these topics have reached a stage where reviews of the present state of knowledge are useful. The application of ab initio methods to calculations of hydration and conformation of small molecules has a longer history, but here again a critical summary is timely. The role of solvent effects in reaction kinetics and mechanisms should have had a place in Volume 2 of this treatise, but, as sometimes happens, the author who had taken on this task failed tQ live up to his promise. However, since 1972 the physical chemistry of mixed aqueous solvents has made considerable strides, so that the belated discussion of this topic (by a new author) is built on evidence that was not available at the time of publication of Volume 2.

This volume is the last in the series comprising "Water-A Comprehensive Treatise. " It was originally planned to combine aqueous solutions of macro molecules and disperse systems in one volume, but largely because of the extensive coverage required by recent developments in aqueous solutions of proteins and synthetic polymers I decided to separate topics dealing with water in disperse systems. The systems treated in the present volume are of a complex nature so that the theoretical frameworks established earlier in Volume 1 and utilized in Volumes 2 and 3 cannot at the present time be applied. On the other hand the systems discussed in Volumes 4 and 5 in particular, border on the many biological and technological areas where important attributes are related to the common factor-water. Included among such diverse problem areas are food processing and preservation, cryopreservation, paper and textile finishing, membrane processes, hemodynamics, etc. It is to be hoped that in days to come some of the results and principles discussed in these five volumes can be applied to improve our understanding of the complex in teractions in medically and industrially important spheres of scientific ac tivity. An age seems to have passed since the concept of creating this treatise was first discussed, and since work began on Volume 1, much has happened in the science of Water; some of the recent developments were highlighted at this year's Gordon Research Conference in Plymouth, N. H.

V.4 Aqueous solutions of amphiphiles and macromolecules. Author, subject and compound indexes.