Colloids are submicron particles that are ubiquitous in nature (milk, clay, blood) and industrial products (paints, drilling fluids, food). It has been known for a long time that adding salt or polymer influences the characteristics of colloidal suspensions. Think of the Egyptians who engineered ink by adding gum Arabic to soot particles a few thousand years ago. Unknowingly, they were taking advantage of the anchoring of the polysaccharides onto the colloids to provide the stabilization of the soot particles that eventually provided an ink to write on papyrus. The effect of charges and polymers attached to the surface of colloidal particles on their stability has been understood and studied extensively in the last century. But the more elusive, albeit ubiquitous, effects of the addition of free polymers and small colloids as depletants to colloidal dispersions have become in focus recently. In recent decades it has become clear that adding such depletants allows one to tune the interactions between the colloids and in this way control the stability, structure and rheological properties of colloidal dispersions. This book offers a concise introduction to the fundamentals of depletion effects and their influence on the phase behavior of colloidal dispersions. These fundamental principles promote insight and the intuitive sense needed to isolate issues related to depletion effects in technological problems and design critical experiments. In an introductory chapter, the authors provide a historical perspective and the applications of depletion effects not only in colloid science but also in biology, medicine and technology. In the subsequent chapter they address the basics of depletion interactions, including the effects of anisotropic depletants. The next chapter covers the basics of phase behavior in colloidal dispersions, followed by extensions towards mixtures of spherical colloids with polymers or small colloids inducing depletion forces. Finally, the authors consider depletion effects in suspensions of rod-like colloids. Throughout the book, conceptual explanations are accompanied by experimental and computer simulation results. This is an ideal book for advanced undergraduates and graduate students in physical chemistry, chemical engineering and soft matter physics. It provides the basic knowledge of depletion interactions and phase behaviour in general. Experienced scientists and engineers working on polymers, particles or colloidal dispersions, may also find this book useful.

Autorentext

Henk N.W. Lekkerkerker (1946) studied chemistry at Utrecht University (The Netherlands) and obtained his doctorate at the University of Calgary (Canada) in 1971. He then moved to Brussels initially as a postdoctoral fellow at the Université Libre de Bruxelles (Belgium) and subsequently became a Professor of Theoretical Physical Chemistry at the Vrije Universiteit Brussel. From 1985 till present he is a Professor of Physical Chemistry at the Van 't Hoff laboratory, Utrecht University and since 2006 he is also Academy Professor of the Royal Netherlands Academy of Arts and Sciences. He received the Bakhuys Roozeboom Gold Medal, the Onsager Medal and the Liquid Matter Prize for his work on phase behavior of colloidal dispersions.

Remco Tuinier (1971) studied food science at Wageningen University (The Netherlands) and performed his PhD work at the NIZO food research institute and Wageningen University on colloid-polymer mixtures. Subsequently, he worked as Postdoctoral fellow at Utrecht University and in 2001 became a staff member at the Forschungszentrum Jülich, Germany. From 2008-2015 he worked at DSM Research, Geleen, The Netherlands as Senior and Principal Scientist Colloids & Interfaces. Since 2013 he is part-time professor at Utrecht University. In 2015 he became full professor of physical chemistry at Eindhoven University of Technology, the Netherlands. The authors are collecting feedback and corrections for the second edition. Please send your comments to: depletionbook@gmail.com

Inhalt

Preface 1 Introduction 1.1 Colloidal interactions 1.2 The Von Guericke force 1.3 Depletion 1.4 Manifestations of depletion effects in colloid + polymer mixtures 1.5 Historical overview on depletion 1.5.1 Experimental observations before the 1950s 1.5.2 Attractive forces in Nagoya 1.5.3 Systematic studies after AO 1.6 Outline of this book 2 Depletion Interaction 2.1 Depletion interaction due to penetrable spheres 2.1.1 Depletion interaction between two flat plates 2.1.2 Depletion interaction between two spheres 2.2 Depletion interaction due to ideal polymers 2.2.1 Depletion interaction between two flat plates 2.2.2 Interaction between two spheres 2.3 Depletion interaction due to excluded volume polymers 2.3.1 Characteristic length scales in polymer solutions 2.3.2 Osmotic pressure of polymer solutions 2.3.3 Depletion thickness due to excluded volume polymers 2.3.4 Evaluation of the depletion interaction due to excluded volume polymers 2.4 Depletion interaction due to spheres 2.4.1 Concentration profiles near a hard wall and between two hard walls 2.4.2 Depletion interaction between two flat plates 2.4.3 Depletion interaction between two (big) spheres 2.5 Depletion interaction due to rods 2.5.1 Depletion interaction between two flat plates 2.5.2 Interaction between two (big) colloidal spheres using the Derjaguin approximation 2.6 Depletion interaction due to disks 2.6.1 Depletion interaction between two flat plates 2 .6.2 Interaction bet

ween two (big) colloidal spheres using the Derjaguin approximation 2.7 Measurements of depletion interactions 2.7.1 Atomic force microscope 2.7.2 Total internal eflection microscopy 2.7.3 Optical tweezers 3 Phase transitions of hard spheres plus depletants; basics 3.1 Introduction -colloid/atom analogy 3.2 The hard sphere fluid-crystal transition 3.3 Free volume theory Appendix 3.1. Statistical Mechanical derivation of the Free Volume Theory 4 Stability of colloid-polymer mixtures 4.1 Experimental state diagrams of colloid-polymer mixtures 4.2 Phase behaviour of colloid + ideal polymer mixtures 4.3 Phase behaviour of sphere plus interacting polymer mixtures; GFVT 4.3.1 Depletion thickness and osmotic pressure 4.3.2 Protein Limit 4.4 Non-equilibrium phenomena 4.4.1 Unmixing kinetics 4.4.2 Aggregation and gelation 4.4.3 Depletion effects on colloidal glasses 5 Phase transitions of hard spheres plus colloids 5.1 Free volume theory for big plus small hard spheres 5.2 Phase behavior of mixed spheres 5.2.1 Phase separation in binary mixtures differing only in diameter 5.2.2 Mixtures of latex particles and micelles 5.2.3 Oil-in-water emulsion particles and micelles of the stabilizing surfactant 5.3 free volume theory for sphere-rod mixtures 5.4 Phase behaviour of sphere-rod mixtures 6 Suspensions of rod-like colloids plus polymers 6.1 Onsager theory of the isotropic-nematic transition 6.2 Scaled particle theory of the isotropic-nematic transition 6.3 Isotropic-nematic phase behaviour of rods plus phs 6.4 I-N phase behaviour of rods plus polymers 6.4.1 Rod-like colloids plus ideal polymers 6.4.2 Rod-like colloids plus interacting polymers 6.5 Experiments on rod/polymer mixtures 6.5.1 Stiff virusparticles + polymer 6.5.2 Cellulose nanocrystals + polymer 6.5.3 Sterically stabilized colloidal boehmite rods + polymer 6.6 Rod/polymer mixtures: full phase diagrams. 6.7 Concluding remarks. List of symbols Index