In recent years, a growing number of engineering applications of light weight and energy efficient plastics can be found in high quality parts vital to the func tioning of entire equipments and structures. Improved mechanical properties, especially balance of stiffness and toughness, are among the most frequently desired features of the new materials. In addition, reduced flammability is con sidered the single most important requirement for further expansion of plastics into large volume and demanding markets such as construction and mass trans port. Production of power cables also requires flame retardant cable jacketing plastics to replace or at least to reduce consumption of environmentally unsound PVC. The two principal ways to achieve the goals mentioned above include the development of completely new thermoplastic polymers and various modifica tions of the existing ones. Development and commercialization of a new ther moplastic require mobilization of large human and financial resources, the lat ter being within the range from $100 million to $10 billion, in comparison to $100 thousand to $10 million needed to develop and commercialize polymeric mate rial with prescribed end use properties using physical or chemical modification of an existing plastic. In addition, the various markets utilizing thermoplastics demand large flexibility in material properties with only moderate volumes, at the best.

This book presents the most comprehensive analysis of bonding in polyoxometalates and related oxides based on classical bonding concepts and the bond valence model. Numerous tables and figures underline and illuminate the results, making it a valuable resource.

Over the past four decades polymers containing imide groups (usually as build ing blocks of the polymer backbone) have attracted increasing interest of sci entists engaged in fundamental research as well as that of companies looking into their application and commercialization. This situation will apparently continue in the future and justifies that from time to time reviews be published which sum up the current state of knowledge in this field. Imide groups may impart a variety of useful properties to pol~'mers, e. g. , thermal stability chain stiffness, crystallinity, mesogenic properties, photoreactivity etc. These lead to a broad variety of potential applications. This broad and somewhat heteroge neous field is difficult to cover in one single review or monograph. A rather com prehensive monograph was edited four years ago by K. Mittal, mainly concen trating on procedures and properties of technical interest. Most reviews presented in this volume of Advances in Polymer Science focus on fundamen tal research and touch topics not intensively discussed in the monograph by K. Mittal. Therefore, the editor of this work hopes that the reader will appreci ate finding complementary information. Finally I wish to thank all the contributors who made this work possible and I would like to thank Dr. Gert Schwarz for the revision of the manuscripts of the contributions 3 and 4. Hamburg, September 1998 Hans R. Kricheldorf Contents Nanoporous Polyimides J. L. Hedrick, K. R. Carter, l. W. Labadie, R. D. Miller, W.

This volume of the series gives an overview on Rigid Polymer Networks written by two reputed experts in the field. A broad range of densely-branched, highly-crosslinked aromatic networks and gels of increasing rigidity are discussed, with special emphasis on aromatic rigid liquid-crystal polymer networks. The synthetic procedures to create the networks are briefly described and extensively referenced. Features of one-step and two-step rigid networks in their pre-gel and post-gel states are discussed. Some first steps are then taken in the theoretical treatment of LCP networks with long aromatic segments of decreasing stiffness. The current state of theory dealing with the broader class of highly-crosslinked rigid aromatic networks and gels is finally mentioned.

This Volume 44 of Advances in Solid State Physics contains the written versions of most of the invited lectures of the Spring Meeting of the Condensed Matter Physics section of the Deutsche Physikalische Gesellschaft held from March 8 to 12, 2004 in Regensburg, Germany. Many of the topical talks given at the numerous and very lively symposia are also included. They have covered extremely interesting and timely subjects. Thus the book truly reflects the status of the field of solid state physics in 2004, and indicates its importance, not only in Germany but also internationally.

Semiconductor power devices are the heart of power electronics. They determine the performance of power converters and allow topologies with high efficiency. Semiconductor properties, pn-junctions and the physical phenomena for understanding power devices are discussed in depth. Working principles of state-of-the-art power diodes, thyristors, MOSFETs and IGBTs are explained in detail, as well as key aspects of semiconductor device production technology. In practice, not only the semiconductor, but also the thermal and mechanical properties of packaging and interconnection technologies are essential to predict device behavior in circuits. Wear and aging mechanisms are identified and reliability analyses principles are developed. Unique information on destructive mechanisms, including typical failure pictures, allows assessment of the ruggedness of power devices. Also parasitic effects, such as device induced electromagnetic interference problems, are addressed. The book concludes with modern power electronic system integration techniques and trends.

"The importance of knowledge consists not only in its direct practical utility but also in the fact the it promotes a widely contemplative habit of mind; on this ground, utility is to be found in much of the knowledge that is nowadays labelled 'useless'. " Bertrand Russel, In Praise of Idleness, London (1935) "Why are scientists in so many cases so deeply interested in their work ? Is it merely because it is useful ? It is only necessary to talk to such scientists to discover that the utilitarian possibilities of their work are generally of secondary interest to them. Something else is primary. " David Bohm, On creativity, Abingdon (1996) In this volume, the dynamical critical behaviour of many-body systems far from equilibrium is discussed. Therefore, the intrinsic properties of the - namics itself, rather than those of the stationary state, are in the focus of 1 interest. Characteristically, far-from-equilibrium systems often display - namical scaling, even if the stationary state is very far from being critical. A 1 As an example of a non-equilibrium phase transition, with striking practical c- sequences, consider the allotropic change of metallic ?-tin to brittle ?-tin. At o equilibrium, the gray ?-Sn becomes more stable than the silvery ?-Sn at 13. 2 C. Kinetically, the transition between these two solid forms of tin is rather slow at higher temperatures. It starts from small islands of ?-Sn, the growth of which proceeds through an auto-catalytic reaction.

The book aims to describe the microscopic characterization of the soft matter in the light of new advances acquired in the science of microscopy techniques like AFM; SEM; TEM etc. It does not focus on the traditional information on the microscopy methods as well as systems already present in different books, but intends to answer more fundamental questions associated with commercially important systems by using new advances in microscopy. Such questions are generally not answered by other techniques. The contents of the book also reflect this as the chapters are not based on describing only material systems, but are based on the answering the problems or questions arising in their characterization. Both qualitative as well as quantitative analysis using such microscopic techniques is discussed. Moreover, efforts have been made to provide a broader reach as discussions on both polymers as well as biological matter have been included as different sections. Such a text with comprehensive overview of the various characterization possibilities using microscopy methods can serve as a valuable reference for microscopy experts as well as non-experts alike

Some years ago it was not uncommon for materials scientists, even within the electronics industry, to work relatively independently of device engi neers. Neither group had a means to determine whether or not the materials had been optimized for application in specific device structures. This mode of operation is no longer desirable or possible. The introduction of a new material, or a new form of a well known material, now requires a close collaborative effort between individuals who represent the disciplines of materials preparation, materials characterization, device design and pro cessing, and the analysis of the device operation to establish relationships between device performance and the materials properties. The develop ment of devices in heteroepitaxial thin films has advanced to the present state specifically through the unusually close and active interchange among individuals with the appropriate backgrounds. We find no book available which brings together a description of these diverse disciplines needed for the development of such a materials-device technology. Therefore, the authors of this book, who have worked in close collaboration for a number of years, were motivated to collect their experiences in this volume. Over the years there has been a logical flow of activity beginning with heteroepi taxial silicon and progressing through the III-V and II-VI compounds. For each material the early emphasis on material preparation and characteriza tion later shifted to an emphasis on the analysis of the device characteristics specific to the materials involved.

Toyiochi Tanaka, Mitsuhiro Shibayama, "Phase Transitions and related Phenomena of Polymer Gels", Akira Onuki "Theory of Phase Transition in Polymer Gels", Alexei Khokhlov, Sergei Starodybtzev, Valentina Vasilevskaya "Conformational Transitions in Polymer Gels: Theory and Experiment", Michal Ilavsky " Effect on Phase Transition on Swellingand Mechanical Behavior of Synthetic Hydrogels", Shozaburo Saito , M. Konno, H. Inomata "Volume Phase Transition of N-Alkylacrylamide Gels", Ronald Siegel "Hydrophobic Weak Polyelectrolyte Gels: Studies of Swelling Equilibria and Kinetics".

PEO Unsaturated Macromonomers ................... 21 PEO Saturated Macromonomers ..................... 24 PEO Block and Graft Copolymers .................... 25 Dispersion Polymerization of PEO Macromonomers ......... 27 Copolymerization of PEO Macromonomers with Styrene ...... 27 Copolymerization of PEO Macromonomers with Alkyl Acrylates and Methacrylates .................... 33 Emulsion Polymerization of PEO Macromonomers ......... 34 Homopolymerization of PEO Macromonomers ............ 34 Copolymerization of PEO Macromonomers with Styrene ...... 39 Copolymerization of PEO Macromonomers with Other Comonomers ............................ 45 Polymerization of PEO Macromonomers in Other Disperse Systems .......................... 48 Conclusion ................................. 50 References ................................. 52 List of Abbreviations and Symbols A acrylic group second virial coefficient A2 AA acrylic acid AVA 4,4'-azobis(4-cyanovaleric acide) AIBN 2,2'-azobiisobutyronitrile B A butyl acrylate BzMA benzyl methacrylate BMA butyl methacrylate CAC critical association concentration concentration of monomer in water cw concentration of polymer micelle concentration CMC critical CFC critical flocculation concentration CFT critical flocculation temperature chain length (CL) Radical Polymerization of Polyoxyethylene Macromonomers in Disperse Systems 3 methyl Cl t-butyl tC4 chain transfer constant to stabilizer cs chain transfer to solvent css chain transfer constant for transfer to polymeric stabilizer CSP D particle diameter DLS dynamic light scattering volume median diameter D50 final particle diameter " f DBP dibenzoyl peroxide number average degree of polymerization DPn diffusion coefficient of the radical in water " w overall activation energy EO activation energy for propagation E activation energy for termination E t activation energy for decomposition of initiator Ed EO ethylene oxide unit f initiator efficiency monomer feed composition fw graft available G a graft required G r HLB hydrofile-lipophile balance

Soft matter and biological systems pose many challenges for theoretical, experimental and computational research. From the computational point of view, these many-body systems cover variations in relevant time and length scales over many orders of magnitude. Indeed, the macroscopic properties of materials and complex fluids are ultimately to be deduced from the dynamics of the microsopic, molecular level. In these lectures, internationally renowned experts offer a tutorial presentation of novel approaches for bridging these space and time scales in realistic simulations. This volume addresses graduate students and nonspecialist researchers from related areas seeking a high-level but accessible introduction to the state of the art in soft matter simulations.

The liquid crystalline state may be identified as a distinct and unique state of matter which is characterised by properties which resembles those of both solids and liquids. It was first recognised in the middle of the last century through the study of nerve myelin and derivatives of cholesterol. The research in the area really gathered momentum, however, when as a result of the pioneering work of Gray in the early 1970's organic compounds showing liquid crystalline properties were shown to be suitable to form the basis of display devices in the electronic products. The study of liquid crystals is truly multidisciplinary and has attached the attention of physicists, biologists, chemists, mathematicians and electronics engineers. It is therefore impossible to cover all these aspects fully in two small volumes and therefore it was decided in view of the overall title of the series to concentrate on the structural and bonding aspects of the subject. The Chapters presented in these two volumes have been organised to cover the following fundamental aspects of the subject. The calculation of the structures of liquid crystals, an account of their dynamical properties and a discussion of computer simulations of liquid crystalline phases formed by Gay Berne mesogens. The relationships between molecular conformation and packing are analysed in some detail. The crystal structures of liquid crystal mesogens and the importance of their X ray scattering properties for characterisational purposes are discussed.

Composed of papers written by leading engineers and scientists in the field, this valuable collection reports the most recent advances in cryocooler development, contains extensive performance test results and comparisons, and relates the latest experience in integrating cryocoolers into advanced applications.

Proceedings of the 1991 Cryogenic Engineering Conference held in Huntsville, Alabama, June 11-14, 1991.

In the future, many modern materials will be increasingly based on the assembly of preformed molecular entities. Their structural characteristics and functional prop- ties will be programmed at the molecular level and their formation as a completed entity will be achieved by self-assembly processes. This in essence is a bottom-up approach and its success will require a deep understanding not only of the chemistry of intermolecular interactions and associations but also of self-assembly processes in the condensed phase. Among various interesting innovations brought about by the development of supramolecular chemistry, supramolecular synthesis is a part- ularly powerful approach for the design and generation of molecular architectures displaying both structural and functional complexity. The combination of mol- ular synthesis (which allows chemists to design and prepare extremely sophis- cated biotic and abiotic molecules through the interconnection of atoms or group of atoms by strong covalent bonds) and supramolecular synthesis (which orch- trates the association of molecules by recognition processes through the use of weak and reversible interactions) opens up endless structural and functional possibilities. Following the perceptive observation by Dunitz that "A crystal is, in a sense, the supramolecule par excellence", molecular crystals may be seen as in?nite periodic architectures resulting from the interconnection of building blocks or tectons ca- ble of self-assembling through speci?c recognising events.

Lasers can readily remove very thin layers from small areas of a material and can thus be used both to control the structure of the surface and to determine its composition. Laser ablation thus has a wide variety of applications - from re-shaping the cornea of the eye to correct vision and micro-machining electronic devices, to detection of minute contaminants on catalysts. This book is the proceedings of one ofthe first workshops held on this topic.

As Chairmen of the Electrochemistry and Molten Salts Discussion Groups of the Chemical Society, it gave us great pleasure to welcome the confer ence Highly Concentrated Aqueous Solutions and Molten Salts, which our Groups cosponsored, at St. John's College, Oxford in July 1978. During the meeting the editors of the present volume, and those giving lectures, came to the conclusion that the verbal presentations deserved to be expanded and to be more widely disseminated in a permanent form. Thus the articles which appear in this volume were commissioned and prepared. A greater exchange of information between aqueous chemists and those concerned with molten salts is to be welcomed and to this end the present volume aims to focus attention on the borderline areas between the two in an attempt to facilitate a wider awareness of the concepts and methods appropriate to the respective specialities. Similarly, and parti cularly in the electrochemical field, a greater exchange of information be tween the academic and industrial practitioners of the subject is desirable. T!1e problems involved are not trivial but when the interactions in these largely (but not wholly) ionic liquids are better understood, this wiii surely be to the benefit of all concerned with solution chemistry. Douglas Inman, Imperial College Chairman, Electrochemistry Group David Kerridge, University of Southampton Chairman, Molten Salts Discussion Group v Preface A number of recent events led to the appearance of this text at this particu lar time.

This volume contains the invited papers and selected contributed papers presented at the biennial International Symposium on ELECTRON COLLISIONS WITH MOLECULES, CLUSTERS AND SURF ACES held at Royal Holloway, University of London from 29th to 30th July, 1993. This Symposium was a Satellite Meeting of the XVIII International Conference on the Physics of Electronic and Atomic Collisions (ICPEAC) and follows a 16 year tradition of Satellite Conferences in related areas of collisions held in association with previous ICPEAC's. In the past each of these electron -molecule symposia covered the broad field of electron-molecule scattering at rather low energies, but also included hot topics. This time as well as covering the whole field, well defined electron collisions with clusters and with particles in the complex potential of a surface were emphasized. Not many details are known about such collisions, although they become more and more important in surface characterisation, plasma-wall interactions, electron induced desorption and reorganisation of adsorbed particles. Recently, much work, theoretical and experimental, has been devoted to electron collisions with rather large carbon, silicon and halogen containing molecules. These problems are of relevance in plasma assisted thin film formation and etching of surfaces and can now be approached with advanced theoretical methods and experimental equipment.

The state-of-the-art in the theoretical statistical physics treatment of the Janus fluid is reported with a bridge between new research results published in journal articles and a contextual literature review. Recent Monte Carlo simulations on the Kern and Frenkel model of the Janus fluid have revealed that in the vapor phase, below the critical point, there is the formation of preferred inert clusters made up of a well-defined number of particles: the micelles and the vesicles. This is responsible for a re-entrant gas branch of the gas-liquid binodal. Detailed account of this findings are given in the first chapter where the Janus fluid is introduced as a product of new sophisticated synthesis laboratory techniques. In the second chapter a cluster theory is developed to approximate the exact clustering properties stemming from the simulations. It is shown that the theory is able to reproduce semi-quantitatively the micellization phenomenon.