Advances in Dielectrics – serie

This book introduces the ideas and concepts of nonlinear dielectric spectroscopy, outlines its history, and provides insight into the present state of the art of the experimental technology and understanding of nonlinear dielectric effects. Emphasis is on what can be learned from nonlinear experiments that could not be derived from the linear counterparts. The book explains that nonlinear dielectric spectroscopy can be used as a tool to measure structural recovery or physical aging, as well as connections between dynamics and thermodynamic variables such as enthalpy and entropy. Supercooled liquids in their viscous regime are ideal candidates for investigating nonlinear effects, because they are particularly sensitive to changes in temperature, and thus also to changes in the electric field. Other interesting materials covered are plastic crystals and complex liquids near criticality. The book also points out that, compared with other techniques such as mechanical shear experiments, the nonlinear regime of dielectric spectroscopy is special in the sense that the energies involved always remain small compared with thermal energies. To demonstrate this, nonlinear features of mechanical experiments are discussed. Theoretical approaches to nonlinear effects are particularly complicated because the tools available for the linear regime no longer apply. As a result, there is no single generally accepted theory to nonlinear dielectric responses of real liquids. Various approaches to nonlinear dielectric features have been reported, and the different aspects are communicated in several chapters. The book communicates recent progress most effectively through individual contributions from specialists in their respective fields.Chapter 'Third and Fifth Harmonic Responses in Viscous Liquids' is available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.

The dielectric properties especially of glassy materials are nowadays explored at widely varying temperatures and pressures without any gap in the spectral range from µHz up to the Infrared, thus covering typically 20 decades or more. This extraordinary span enables to trace the scaling and the mutual interactions of relaxation processes in detail, e.g. the dynamic glass transition and secondary relaxations, but as well far infrared vibrations, like the Boson peak. Additionally the evolution of intra-molecular interactions in the course of the dynamic glass transition is also well explored by (Fourier Transform) Infrared Spectroscopy. This volume within 'Advances in Dielectrics' summarizes this knowledge and discusses it with respect to the existing and often competing theoretical concepts.

This book presents new approaches that offer a better characterization of the interrelationship between crystalline and amorphous phases. In recent years, the use of dielectric spectroscopy has significantly improved our understanding of crystallization. The combination of modern scattering methods, using either synchrotron light or neutrons and infrared spectroscopy with dielectrics, is now helping to reveal modifications of both crystalline and amorphous phases. In turn, this yields insights into the underlying physics of the crystallization process in various materials, e.g. polymers, liquid crystals and diverse liquids. The book offers an excellent introduction to a valuable application of dielectric spectroscopy, and a helpful guide for every scientist who wants to study crystallization processes by means of dielectric spectroscopy.

This book presents new approaches that offer a better characterization of the interrelationship between crystalline and amorphous phases. In recent years, the use of dielectric spectroscopy has significantly improved our understanding of crystallization. The combination of modern scattering methods, using either synchrotron light or neutrons and infrared spectroscopy with dielectrics, is now helping to reveal modifications of both crystalline and amorphous phases. In turn, this yields insights into the underlying physics of the crystallization process in various materials, e.g. polymers, liquid crystals and diverse liquids. The book offers an excellent introduction to a valuable application of dielectric spectroscopy, and a helpful guide for every scientist who wants to study crystallization processes by means of dielectric spectroscopy.

The book presents recent developments in the field of composites, investigated by Broadband Dielectric Spectroscopy (BDS) and sheds a special focus on nanocomposites. This volume compares the results obtained by BDS with data from other methods like hyphenated calorimetry, dynamical-mechanical spectroscopy, NMR spectroscopy and neutron scattering. The addressed systems range from all kinds of model systems, such as polymers filled with spherical silica particles, advanced materials such as polymers with molecular stickers or hyperbranched polymer-based matrices to industrially significant systems, like epoxy-based materials. The book offers an excellent insight to a valuable application of dielectric spectroscopy and it is a helpful guide for every scientist who wants to study dynamics in composite materials.

The book presents recent developments in the field of composites, investigated by Broadband Dielectric Spectroscopy (BDS) and sheds a special focus on nanocomposites. This volume compares the results obtained by BDS with data from other methods like hyphenated calorimetry, dynamical-mechanical spectroscopy, NMR spectroscopy and neutron scattering. The addressed systems range from all kinds of model systems, such as polymers filled with spherical silica particles, advanced materials such as polymers with molecular stickers or hyperbranched polymer-based matrices to industrially significant systems, like epoxy-based materials. The book offers an excellent insight to a valuable application of dielectric spectroscopy and it is a helpful guide for every scientist who wants to study dynamics in composite materials.

This volume highlights the potential of an experimental approach, which offers a relatively simple and inexpensive alternative to conventional techniques. Its basis is the set of changes of thermodynamic variables that occur when an electric field is applied to an ideal dielectric. If these processes are experimentally measured as a function of temperature, and suitable hypotheses are met, many thermodynamic quantities can be derived from dielectric physical quantities. This enables a shift from standard dielectric thermal analysis to a more targeted dielectric calorimetry.A central parameter affected by the electric field is the entropy variation known as Fröhlich entropy (FE), introduced by H. Fröhlich. When the imaginary part of the static dielectric function is negligible, far from resonances, FE can be calculated, under the right assumptions, from the real part of the dielectric function. Fröhlich suggested that FE reflects the state of order of the system, making it a useful figure of merit.Assuming this interpretation, FE values offer insight into the behavior of materials, particularly with respect to temperature, phase stability, transitions, and order–disorder processes. Because the underlying assumptions are weak, the method applies to many physical systems and effectively extends traditional dielectric techniques.FE estimation has been successfully used across diverse areas of condensed matter physics, including dipolar liquids, liquid and nematic crystals, dipolar glasses, organic molecular crystals, semiconductors, metallic nanoparticles, inorganic disordered ferroelectrics, proteins, and enzymes. This breadth demonstrates its reliability and its significant, still underexplored, potential.

This book describes the dynamics of low molecular weight and polymeric molecules when they are constrained under conditions of geometrical confinement. It covers geometrical confinement in different dimensionalities:(i) in nanometer thin layers or self supporting films (1-dimensional confinement)(ii) in pores or tubes with nanometric diameters (2-dimensional confinement)(iii) as micelles embedded in matrices (3-dimensional) or as nanodroplets.The dynamics under such conditions have been a much discussed and central topic in the focus of intense worldwide research activities within the last two decades. The present book discusses how the resulting molecular mobility is influenced by the subtle counterbalance between surface effects (typically slowing down molecular dynamics through attractive guest/host interactions) and confinement effects (typically increasing the mobility). It also explains how these influences can be modified and tuned, e.g. through appropriate surface coatings, film thicknesses or pore diameters. "Dynamics in Confinement" sums up the present state-of-the-art and introduces to the analytical methods of choice for the study of dynamics in nanometer-scale confinement.

This book discusses the mechanisms of electric conductivity in various ionic liquid systems (protic, aprotic as well as polymerized ionic liquids). It hence covers the electric properties of ionic liquids and their macromolecular counterpanes, some of the most promising materials for the development of safe electrolytes in modern electrochemical energy devices such as batteries, super-capacitors, fuel cells and dye-sensitized solar cells. Chapter contributions by the experts in the field discuss important findings obtained using broadband dielectric spectroscopy (BDS) and other complementary techniques. The book is an excellent introduction for readers who are new to the field of dielectric properties of ionic conductors, and a helpful guide for every scientist who wants to investigate the interplay between molecular structure and dynamics in ionic conductors by means of dielectric spectroscopy.

This book describes the dynamics of low molecular weight and polymeric molecules when they are constrained under conditions of geometrical confinement. It covers geometrical confinement in different dimensionalities:(i) in nanometer thin layers or self supporting films (1-dimensional confinement)(ii) in pores or tubes with nanometric diameters (2-dimensional confinement)(iii) as micelles embedded in matrices (3-dimensional) or as nanodroplets.The dynamics under such conditions have been a much discussed and central topic in the focus of intense worldwide research activities within the last two decades. The present book discusses how the resulting molecular mobility is influenced by the subtle counterbalance between surface effects (typically slowing down molecular dynamics through attractive guest/host interactions) and confinement effects (typically increasing the mobility). It also explains how these influences can be modified and tuned, e.g. through appropriate surface coatings, film thicknesses or pore diameters. "Dynamics in Confinement" sums up the present state-of-the-art and introduces to the analytical methods of choice for the study of dynamics in nanometer-scale confinement.

The dielectric properties especially of glassy materials are nowadays explored at widely varying temperatures and pressures without any gap in the spectral range from µHz up to the Infrared, thus covering typically 20 decades or more. This extraordinary span enables to trace the scaling and the mutual interactions of relaxation processes in detail, e.g. the dynamic glass transition and secondary relaxations, but as well far infrared vibrations, like the Boson peak. Additionally the evolution of intra-molecular interactions in the course of the dynamic glass transition is also well explored by (Fourier Transform) Infrared Spectroscopy. This volume within 'Advances in Dielectrics' summarizes this knowledge and discusses it with respect to the existing and often competing theoretical concepts.

This book introduces the ideas and concepts of nonlinear dielectric spectroscopy, outlines its history, and provides insight into the present state of the art of the experimental technology and understanding of nonlinear dielectric effects. Emphasis is on what can be learned from nonlinear experiments that could not be derived from the linear counterparts. The book explains that nonlinear dielectric spectroscopy can be used as a tool to measure structural recovery or physical aging, as well as connections between dynamics and thermodynamic variables such as enthalpy and entropy. Supercooled liquids in their viscous regime are ideal candidates for investigating nonlinear effects, because they are particularly sensitive to changes in temperature, and thus also to changes in the electric field. Other interesting materials covered are plastic crystals and complex liquids near criticality. The book also points out that, compared with other techniques such as mechanical shear experiments, the nonlinear regime of dielectric spectroscopy is special in the sense that the energies involved always remain small compared with thermal energies. To demonstrate this, nonlinear features of mechanical experiments are discussed. Theoretical approaches to nonlinear effects are particularly complicated because the tools available for the linear regime no longer apply. As a result, there is no single generally accepted theory to nonlinear dielectric responses of real liquids. Various approaches to nonlinear dielectric features have been reported, and the different aspects are communicated in several chapters. The book communicates recent progress most effectively through individual contributions from specialists in their respective fields.Chapter 'Third and Fifth Harmonic Responses in Viscous Liquids' is available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.

This book discusses the mechanisms of electric conductivity in various ionic liquid systems (protic, aprotic as well as polymerized ionic liquids). It hence covers the electric properties of ionic liquids and their macromolecular counterpanes, some of the most promising materials for the development of safe electrolytes in modern electrochemical energy devices such as batteries, super-capacitors, fuel cells and dye-sensitized solar cells. Chapter contributions by the experts in the field discuss important findings obtained using broadband dielectric spectroscopy (BDS) and other complementary techniques. The book is an excellent introduction for readers who are new to the field of dielectric properties of ionic conductors, and a helpful guide for every scientist who wants to investigate the interplay between molecular structure and dynamics in ionic conductors by means of dielectric spectroscopy.

Pressure is one of the essential thermodynamic variables that, due to some former experimental difficulties, was long known as the “forgotten variable.” But this has changed over the last decade. This book includes the most essential first experiments from the 1960's and reviews the progress made in understanding glass formation with the application of pressure in the last ten years. The systems include amorphous polymers and glass-forming liquids, polypeptides and polymer blends. The thermodynamics of these systems, the relation of the structural relaxation to the chemical specificity, and their present and future potential applications are discussed in detail. The book provides (a) an overview of systems exhibiting glassy behavior in relation to their molecular structure and provides readers with the current state of knowledge on the liquid-to-glass transformation, (b) emphasizes the relation between thermodynamic state and dynamic response and (c) shows that the information on the pressure effects on dynamics can be employed in the design of materials for particular applications. It is meant to serve as an advanced introductory book for scientists and graduate students working or planning to work with dynamics. Several scientific papers dealing with the effects of pressure on dynamics have appeared in leading journals in the fields of physics in the last ten years. The book provides researchers and students new to the field with an overview of the knowledge that has been gained in a coherent and comprehensive way.