Electrostatic Effects in Soft Matter and Biophysics NATO Science Series A Series presenting the results of scientific meetings supported under the NArO Science Programme. The Series is published by 10S Press, Amsterdam, and Kluwer Academic Publishers in conjunction with the NATO Scientific Affairs Division Sub-Series 1. Life and Behavioural Sciences 10S Press II. Mathematics, Physics and Chemistry Kluwer Academic Publishers III. Computer and Systems Science 10S Press IV. Earth and Environmental Sciences Kluwer Academic Publishers The NATO Science Series continues the series of books published formerly as the NATO ASI Series. The NATO Science Programme offers support for collaboration in civil science between scientists of countries of the Euro-Atlantic Partnership Council. The types of scientific meeting generally supported are "Advanced Study Institutes" and "Advanced Research Workshops", and the NATO Science Series collects together the results of these meetings. The meetings are co-organized bij scientists from NATO countries and scientists from NATO's Partner countries - countries of the CIS and Central and Eastern Europe. Advanced Study Institutes are high-Ievel tutorial courses offering in-depth study of latest advances in a field. Advanced Research Workshops are expert meetings aimed at critical assessment of a field, and identification of directions for future aetion. As a consequence of the restrueturing of the NATO Science programme in 1999, the NATO Science Series was re-organized to the four sub-series noted above. Please consult the following web sites for information on previous volumes published in the Series. http://www.nato.intlscience http://www.wkap.nl http://www.iospress.nl http://www.wtv-books.de/nato-pco.htm Series II: Mathematics, Physics and Chemistry - Voi. 46 Electrostatic Effects in Soft Matter and Biophysics edited by Christian Holm Max-Planck-Institut fur Polymerforschung, Mainz, Germany Patrick Kekicheff Institut Charles Sadron, C.N.R.S., Strasbourg, France and Rudolf Podgornik Department of Physics, University of Ljubljana, Ljubljana, Slovenia SPRINGER-SCIENCE+BUSINESS MEDIA, B.V. Proceedings of the NATO Advanced Research Workshop on Electrostatic Effects in Soft Matter and Biophysics Les Houches, France 1-13 October 2000 A C.I.P. Catalogue record for this book is available from the Library of Congress. ISBN 978-1-4020-0197-0 ISBN 978-94-010-0577-7 (eBook) DOI 10.1007/978-94-010-0577-7 Printed on acid-free paper AII Rights Reserved ©2001 Springer Science+Business Media Dordrecht Originally published by Kluwer Academic Publishers in 2001 Softcover reprint of the hardcover 1st edition 2001 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner. Preface Recently theoretical interest in soft matter has finally caught up with its undisputed practical and technological relevance (high-polymers and elastomers, polyelectrolyte hydrogels, food processing and storage, waste management, new tailored materials, etc.). But even more importantly charged soft matter appears to be at the heart of biotechnologies that are widely believed to be the most important technologies of this century and that already figure in many countries' technological strategies. Recent impetus in the elucidation of the structure of synthetic genosomes, com­ plexes of negatively charged DNA and positively charged lipids, reveals all the subtleties that one has to master in order to be able to study and understand materials that are both soft and charged. Soft charged matter is dominated by the interplay of thermal fluctua­ tions and long-range electrostatic effects on different length and time scales which results in complicated phase diagrams. The range of expertise that one needs to study charged soft matter is so wide, encompassing contin­ uum mechanics, statistical mechanics, field theory, molecular simulations on the theoretical side and sophisticated experimental techniques such as direct force measurements, laser tweezers, light, X-ray and neutron scat­ tering, atomic force microscopy, that it is quite unusual for any university department to be proficient in all its facets. The idea to organize the NATO Advanced Study Institute "Electrostatic Effects in Soft Matter and Biophysics" grew out of a workshop organized by W. Gelbart, A. Parsegian and P. Pincus in Santa Barbara at the ITP in 1998 with a similar theme. While there it was devoted to active researchers, mainly theorists, already familiar with the subject, we felt that it was time to do our share in educating young people to foster the development of this exciting and rapidly growing field. Our aim was to bring together theorists, computer simulators and ex­ perimentalists from research areas as diverse as macromolecular charged colloids and biological materials like DNA. We tried to cover most ba­ sic investigative tools on soft charged materials: analytical methods and approaches, computational tools and tricks of the trade, as well as experi­ mental methods in their different ranges of applicability. The lectures were divided into three thematic blocks: The first block consisted of modern analytical methods used to describe electrostatic interactions between charged soft bodies with fixed charges vi PREFACE immersed in a solution of mobile charge carriers. H. Wennerstrom intro­ duced us to the intermolecular interactions specifically concentrating on the dielectric description in the condensed phase and the Lifshitz theory. R. Kjellander and R. Netz covered in depth the introduction to integral equation theories for the electric double layer and the mean-field Poisson­ Boltzmann equation and all its varied consequences respectively. They also introduced us to the various modern theoretical approaches that go beyond the mean-field approximation. B. Shklovskii introduced us to his approach to electrostatic correlations based on the Wigner crystal model and showed us how different physical problems can be treated with this theory. R. Podgornik reviewed the work on the equation of state in charged macromolecular arrays motivated by recent experimental findings on or­ dered DNA arrays and ordered multilamellar lipid arrays. B. Gelbart and A. Khokhlov reviewed some recent experimental and theoretical insights into DNA condensation and complexation, cationic histone proteins, and chromatin, and told us about new analytical and experimental approaches to understand these biologically important structures. J.-F. Joanny showed us how many problems in the physics of polyelectrolytes and polyam­ pholytes in dilute and semi-dilute solutions can be treated with simple scaling theories. The second block consisted of an introduction to simulational methods of molecular dynamics and Monte Carlo approaches to soft matter sys­ tems with long-range Coulombic interactions. B. Jonsson introduced us to protein electrostatics and compared theoretical approaches to Monte Carlo simulations. We also learned about correlation effects between plates and spheres and the collapse of DNA-like systems due to correlation interaction­ s. K. Kremer prepared a grand tour of polymer simulations, showed us how poor solvent modifies the behavior of polyelectrolytes and gave examples for deviations between theory and simulations for stiff rod polyelectrolytes. The last thematic block treated experimental methods. In depth cover­ age of light, neutron, and X-rays scattering was performed by M. Caffrey, M. Rawiso, and C. Williams. They emphasized new type of experiments like real-time measurements, neutron spin echo, standing X-ray waves, reflectivity, photon correlation spectroscopy, X-ray speckles, and use of X-ray microbeams. A comparison between the main techniques of direct force measurements was presented by P. Kekicheff.These include tech­ niques based on osmotic equilibria, surface force balances, surface force apparatus, atomic force microscope and force measurement techniques on individual freely moving particles (total internal reflection microscopy, etc). The advantages but also the limitations of each technique were underlined and discussed in different systems. In addition new methods applicable to charged systems (colloidal dispersions, polyelectrolytes, DNA assemblies) PREFACE vii were presented (video microscopy, fluorescent microscopy, etc) by D. Grier in conjunction with structural and chemical inhomogeneities, defects and microphases either already present or induced upon confinement or under stress. The chapters in this book do not necessarily follow the courses presented at the school. The authors rather focus on a specific part of the lectures' content, giving adequate background material, trying to provide a reference chapter for further reading. Exactly for this purpose we also added an in­ troductory chapter on the Poisson-Boltzmann description of the cell model, because it lies at the basis of many theoretical advances, and which was not treated in this way in the school. Unfortunately other urgent activities did not allow M. Rawiso to prepare a full version of his contribution in time, but he included a guide to the literature of his lectures. We think that all participants will agree that the Les Houches School provided a unique learning environment for all of us. We had enjoyable mountain trips with the daring experience of how long a return trip through