Preface

Abstract

This special section of Journal of Physics: Condensed Matter contains papers that were presented during a workshop held in Lyon (France) at CECAM (Centre Européen de Calcul Atomique et Moléculaire), 28 - 30 June 1999. The meeting brought together scientists with computational, theoretical, and experimental interests and expertise in the field of effective interactions and phase transitions in colloidal suspensions. Attended by about 30 participants from 11 countries, the workshop comprised 22 talks accompanied by intensive discussions. In recent years colloidal suspensions have been a focus of growing cross-disciplinary attention from the condensed matter physics, physical chemistry, and chemical engineering communities. The unprecedented tunability of interparticle interactions, a correspondingly rich and unusual display of thermodynamic phases, and deep analogies with atomic condensed matter systems have fueled intense scientific inquiry. Recent advances in theoretical, computational, and experimental methods have helped to illuminate the basic nature of microscopic interactions and their influence on macroscopic phenomena. Significant progress has been achieved especially in the area of thermodynamic phase transitions. Theoretical approaches such as density-functional theory and thermodynamic perturbation theory, combined with a variety of simulation techniques, have yielded important insights particularly into first-order phase transitions and the stability of ordered phases. Experimental developments such as total internal reflection microscopy have greatly improved the quantitative analysis of the effective interactions. Charge-stabilized colloids and colloids mixed with adsorbed and non-adsorbing polymers were a particular focus of the meeting. The statistical method of obtaining effective interactions between colloidal particles is to integrate out the microscopic degrees of freedom of particles such as counter-ions, co-ions, and polymers. Although the formal methods are similar, the results are quite different for charged colloids and colloid-polymer mixtures, giving rise to a diversity of phase transition scenarios. The present volume highlights and summarizes some important recent developments in this field. The workshop organizers wish to thank the contributing authors and to acknowledge generous support from CECAM and from the ESF-Programme SIMU (Challenges in Molecular Simulations: bridging the length and time scale gap). Last but not least, they thank the CECAM director, Professor M Mareschal, for his hospitality, and Ms E Crespeau for her excellent local organization. H Löwen (Universität Düsseldorf, Germany) A R Denton (Acadia University, Canada) J K G Dhont (University of Utrecht, The Netherlands)