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The dynamics of colloidal systems
BOOK REVIEW The Dynamics of Colloidal Systems. By WILLIAMB. RUSSEL. University of Wisconsin Press, Madison, Wisconsin, 1987. 119+ xiv. $25.00. This brief volume is a collection of four lectures presented by the author to a chemical engineering audience at the University of Wisconsin. The lectures cover some selected topics on equilibrium and transport properties of colloidal dispersions (and suspensions) and are meant "to provide an introduction and some historical perspective to those not familiar with the field, while still encompassing current research," as stated in the Preface of the book. The lectures appear to have met that objective. As the Preface also notes, "the discussion and bibliography are not comprehensive but selective," and the selection is restricted primarily to the work of the author and his associates. The discussion has an engineering flavor, and this orientation should appeal to those interested in the processing end of the area. The book begins with an introductory chapter that presents an overviewof interparticle forces and hydrodynamic interactions and a brief summary of order/disorder transitions observed in monodispersed colloids. A very brief sketch of Brownian motion in dilute dispersions and an outline of direct measurements of interaction forces are also presented (the latter in more detail than the former). The intent of this chapter is to illustrate what can be gathered about the nature of interactions from direct measurements of forces, properties, and phenomena. Although not a comprehensive foundation for the material that follows in subsequent chapters, this introduction does offer a useful conceptual map of colloidal interactions and phenomena for use as a backdrop for later discussions. The second chapter focuses on flocculation and phase equilibria in dispersed systems. The discussion of flocculation is very brief and is presented only as an illustration of the difference between kinetics-controlled stability or instability of dispersions and the thermodynamic nature of equilibrium phase separation. The material on phase separation is essentially a summary of the discussion sections of the author's previously published papers and highlights the phase equilibria predicted or observed in dispersions of hard spheres in theta solutions and charged spheres in good solutions. The subtleties of projecting phase behavior from the nature of interparticle interactions do not emerge from this treatment, but this chapter succeeds more than the others in achieving the author's intention of illustrating the connection between interaction forces and macroscopic phenomena.
0021-9797/88 $3.00 Copyright © 1988 by Academic Press, Inc. All rights of reproduction in any form reserved.
The last two chapters deal with a few dynamic properties which have practical relevance in processes involving dispersions. Chapter 3 uses the colloidal route to ceramic processing and its relation to the structural aspects of thickening and cake formation in cake filtration as the motivating topics for discussing sedimentation and gradient diffusion in concentrated dispersions. The presentation here does not succeed quite as well as that in Chapter 2 in establishing the link between the interaction forces and the bulk behavior. This is not because the example chosen is speculative (as suggested in the write-up on the jacket of the book), but because the description of the "microstructural model" of cooperative diffusion and the discussion of the link between the local structure and the diffusion and sedimentation coefficients are very sketchy and are too brief to establish the points effectively. In contrast, the last chapter, on rheology, is a good summary of the central features of the hydrodynamic behavior of dispersions as understood presently and follows the structure of Goodwin's articles on this topic ("Specialist Periodical Reports, Colloid Science," Vol. 2. The Chem. Soc., London, 1975; and "Colloidal Dispersions." The Roy. Soc. Chem., London, 1982) and the author's own review in the Journal of Rheology, but in considerably less detail. Unfortunately, some notational, mathematical, and conceptual inconsistencies and errors have been overlooked in the preparation of the original lectures in a book form, and these create a conceptual mine field for the beginners. For example, both the pair-potential and the Nbody configurational energy are denoted by V in Chapter 2 [e.g., Eqs. (2.5), (2.8), and (2.11)]. This interchangeable use of the notation is not a trivial oversight (and is, in fact, surprising), since the central purpose of Chapter 2 is to show how configurational properties, which are determined by complex configurational energy distributions, can be derived from perturbation expansions based on the simpler (and, in principle, measurable) pair interaction energy. Another example is the distribution function Pu (and its equilibrium limit pO) used in Chapter 3. The function Pu is not a probability function as claimed, and its incomplete definition introduces some dimensional inconsistenciesin some of the equations. Similar comments apply in the case of analogous concepts and notations used in Chapter 4 as well. These and other similar oversights are bound to confuse the unsuspecting beginners. The reference lists at the end of the chapters are also somewhat disappointing, especially in view of the stated purpose of the volume. Although the book is addressed to "those unfamiliar with
700 Journal of Colloid and Interface Science, Vol, 124, No. 2, August t988
BOOK REVIEW the field," many fine references of general utility, addressed specifically to such an audience, are not cited. For example, one is surprised to see that Napper's outstanding book on steric dispersions (1) does not find a place in Chapter 2. Similar comments can be made concerning other omissions such as Israelachvili's very useful and convenient reference on interaction forces (2), Hunter's monograph on the practical implications of zeta potential (3) [Hunter's book has an excellent chapter (at an introductory level) on electroviscous and viscoelectric effects in suspensions], and many others (4-8). Even if not cited in the individual chapters, such references could have been collected in a list at the end of the book and would have made the present volume much more accessible. Otherwise the book is well-produced and attractively printed and appears to be free of typographical errors [except for one in the author's name(!) on the inside flap of the jacket] and free of typographical omissions (except for a missing reference in Chapter 3). This volume, despite the (apparently unintended) generality of scope implied by the title, is neither a textbook nor a research monograph (and it does not claim to be either) for it cannot stand alone as a source of concepts, theories, experimental observations, or references. However, it is a good summary of the author's past work in this area and is a welcome addition to the literature.
701 REFERENCES
1. Napper, D. H., "Polymeric Stabilization of Colloidal Dispersions." Academic Press, London/San Diego, 1983. 2. Israelachvili, J. N., "Intermolecular and Surface Forces with Applications to Colloidal and Bio!ogical Systems." Academic Press, London/San Diego, 1985. 3. Hunter, R. J., "Zeta Potential in Colloid Science: Principles and Applications." Academic Press, London/San Diego, 1981. 4. Mahanty, J., and Ninham, B. W., "Dispersion Forces." Academic Press, London / San Diego, 1981. 5. Hirtzel, C. S., and Rajagopalan, R., "Colloidal Phenomena: Advanced Topics," Noyes Press, Park Ridge, NL 1985. 6. Berne, B. J., and Pecora, R., "Dynamic Light Scattering." Wiley-Interscience, New York, 1976. 7. Pecora, R., (Ed.), "Dynamic Light Scattering." Plenum, New York, 1985. 8. Miller, C. A., and Neogi, P., "Interfacial Phenomena: Equilibrium and Dynamic Effects." Dekker, New York, 1985. RAJ RAJAGOPALAN
Deparlment of Chemical Engineering University of Houston Houston, Texas 77004
Journal of Colloid and Interface Science, Vol. 124, No. 2, August 1988
0021-9797/88 $3.00 Copyright © 1988 by Academic Press, Inc. All rights of reproduction in any form reserved.
The last two chapters deal with a few dynamic properties which have practical relevance in processes involving dispersions. Chapter 3 uses the colloidal route to ceramic processing and its relation to the structural aspects of thickening and cake formation in cake filtration as the motivating topics for discussing sedimentation and gradient diffusion in concentrated dispersions. The presentation here does not succeed quite as well as that in Chapter 2 in establishing the link between the interaction forces and the bulk behavior. This is not because the example chosen is speculative (as suggested in the write-up on the jacket of the book), but because the description of the "microstructural model" of cooperative diffusion and the discussion of the link between the local structure and the diffusion and sedimentation coefficients are very sketchy and are too brief to establish the points effectively. In contrast, the last chapter, on rheology, is a good summary of the central features of the hydrodynamic behavior of dispersions as understood presently and follows the structure of Goodwin's articles on this topic ("Specialist Periodical Reports, Colloid Science," Vol. 2. The Chem. Soc., London, 1975; and "Colloidal Dispersions." The Roy. Soc. Chem., London, 1982) and the author's own review in the Journal of Rheology, but in considerably less detail. Unfortunately, some notational, mathematical, and conceptual inconsistencies and errors have been overlooked in the preparation of the original lectures in a book form, and these create a conceptual mine field for the beginners. For example, both the pair-potential and the Nbody configurational energy are denoted by V in Chapter 2 [e.g., Eqs. (2.5), (2.8), and (2.11)]. This interchangeable use of the notation is not a trivial oversight (and is, in fact, surprising), since the central purpose of Chapter 2 is to show how configurational properties, which are determined by complex configurational energy distributions, can be derived from perturbation expansions based on the simpler (and, in principle, measurable) pair interaction energy. Another example is the distribution function Pu (and its equilibrium limit pO) used in Chapter 3. The function Pu is not a probability function as claimed, and its incomplete definition introduces some dimensional inconsistenciesin some of the equations. Similar comments apply in the case of analogous concepts and notations used in Chapter 4 as well. These and other similar oversights are bound to confuse the unsuspecting beginners. The reference lists at the end of the chapters are also somewhat disappointing, especially in view of the stated purpose of the volume. Although the book is addressed to "those unfamiliar with
700 Journal of Colloid and Interface Science, Vol, 124, No. 2, August t988
BOOK REVIEW the field," many fine references of general utility, addressed specifically to such an audience, are not cited. For example, one is surprised to see that Napper's outstanding book on steric dispersions (1) does not find a place in Chapter 2. Similar comments can be made concerning other omissions such as Israelachvili's very useful and convenient reference on interaction forces (2), Hunter's monograph on the practical implications of zeta potential (3) [Hunter's book has an excellent chapter (at an introductory level) on electroviscous and viscoelectric effects in suspensions], and many others (4-8). Even if not cited in the individual chapters, such references could have been collected in a list at the end of the book and would have made the present volume much more accessible. Otherwise the book is well-produced and attractively printed and appears to be free of typographical errors [except for one in the author's name(!) on the inside flap of the jacket] and free of typographical omissions (except for a missing reference in Chapter 3). This volume, despite the (apparently unintended) generality of scope implied by the title, is neither a textbook nor a research monograph (and it does not claim to be either) for it cannot stand alone as a source of concepts, theories, experimental observations, or references. However, it is a good summary of the author's past work in this area and is a welcome addition to the literature.
701 REFERENCES
1. Napper, D. H., "Polymeric Stabilization of Colloidal Dispersions." Academic Press, London/San Diego, 1983. 2. Israelachvili, J. N., "Intermolecular and Surface Forces with Applications to Colloidal and Bio!ogical Systems." Academic Press, London/San Diego, 1985. 3. Hunter, R. J., "Zeta Potential in Colloid Science: Principles and Applications." Academic Press, London/San Diego, 1981. 4. Mahanty, J., and Ninham, B. W., "Dispersion Forces." Academic Press, London / San Diego, 1981. 5. Hirtzel, C. S., and Rajagopalan, R., "Colloidal Phenomena: Advanced Topics," Noyes Press, Park Ridge, NL 1985. 6. Berne, B. J., and Pecora, R., "Dynamic Light Scattering." Wiley-Interscience, New York, 1976. 7. Pecora, R., (Ed.), "Dynamic Light Scattering." Plenum, New York, 1985. 8. Miller, C. A., and Neogi, P., "Interfacial Phenomena: Equilibrium and Dynamic Effects." Dekker, New York, 1985. RAJ RAJAGOPALAN
Deparlment of Chemical Engineering University of Houston Houston, Texas 77004
Journal of Colloid and Interface Science, Vol. 124, No. 2, August 1988