Principles of Soft-Matter Dynamics

Basic Theories, Non-invasive Methods, Mesoscopic Aspects

verfasst von: Rainer Kimmich

Verlag: Springer Netherlands

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik" , Springer Professional "Wirtschaft"

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Über dieses Buch

Practical applications of soft-matter dynamics are of vital importance in material science, chemical engineering, biophysics and biotechnology, food processing, plastic industry, micro- and nano-system technology, and other technologies based on non-crystalline and non-glassy materials.

Principles of Soft-Matter Dynamics. Basic Theories, Non-invasive Methods, Mesoscopic Aspects covers fundamental dynamic phenomena such as diffusion, relaxation, fluid dynamics, normal modes, order fluctuations, adsorption and wetting processes. It also elucidates the applications of the principles and of the methods referring to polymers, liquid crystals and other mesophases, membranes, amphiphilic systems, networks, and porous media including multiphase and multi-component materials, colloids, fine-particles, and emulsions. The book presents all formalisms, examines the basic concepts needed for applications of soft-matter science, and reviews non-invasive experimental techniques such as the multi-faceted realm of NMR methods, neutron and light quasi-elastic scattering, mechanical relaxation and dielectric broadband spectroscopy which are treated and compared on a common and consistent foundation. The standard concepts of dynamics in fluids, polymers, liquid crystals, colloids and adsorbates are comprehensively derived in a step-by-step manner. Principles and analogies common to diverse application fields are elucidated and theoretical and experimental aspects are supplemented by computational-physics considerations.

Principles of Soft-Matter Dynamics. Basic Theories, Non-invasive Methods, Mesoscopic Aspects appeals to graduate and PhD students, post-docs, researchers, and industrial scientists alike.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction

Abstract

It will be pointed out that there is a category of dynamic functions that is used and consequently understood commonly by all methodological communities, namely, temporal correlation functions. A correlation function terminology will be introduced as a sort of lingua franca of molecular dynamics. In a multidisciplinary, multi-methodological field such as soft-matter science, this is expected to facilitate communication among scientists employing different methods in studies of molecular dynamics. In the subsequent chapters, the reader will frequently be reminded of these “common denominators” of dynamic techniques. As further key concepts of pivotal importance, linear-response theory and the fluctuation-dissipation theorem will be outlined.

Rainer Kimmich

Chapter 2. Basic Phenomena and Definitions

Abstract

This chapter provides a compilation of the basic concepts on which soft-matter dynamics is founded. This implies interaction forces, equations of motions, and translational and rotational categories of molecular dynamics. The objective is to have a closed representation in a nomenclature consistent with the subsequent applications. Moreover, a number of less common topics such as Casimir forces and other electrochemical effects will be addressed as well in view of the attention these subjects are attracting in the context of colloidal suspensions and micro-electromechanical systems (MEMS).

Rainer Kimmich

Chapter 3. Noninvasive Methods

Abstract

The global classifications relevant for soft-matter dynamics are coherent and incoherent particle motions and translational and rotational molecular dynamics. The methodology permitting the exploration of these phenomena is of paramount importance for the whole field. In this chapter, the most common techniques suitable for soft-matter studies will be outlined. “Noninvasive” means that the sample materials can be examined in their native form without modifications such as labeling with probe molecules. The same samples can in principle be subjected to different investigations employing complementary techniques. That is, the microstructure remains undistorted by label compounds. Unavoidably, this chapter is relatively long due to the fact that no adequate compendium comprising this particular methodology exists in the literature. Paying tribute to the conceptual philosophy of this book, the specific features of the methods will be presented with particular reference to correlation functions and with a consistent symbolism throughout. The methodological categories under consideration will be diverse NMR-based techniques, quasi-elastic neutron scattering, dynamic light scattering, mechanical relaxation, and dielectric relaxation spectroscopy.

Rainer Kimmich

Chapter 4. Fluid Dynamics

Abstract

Treatments of molecular dynamics in general and especially if they are based on Langevin equations of motions are hardly possible without referring to hydrodynamics. Basic hydrodynamic concepts such as Stokes’ friction law of particles in a viscous medium are ubiquitously employed in molecular dynamics. The present treatise is unique in the sense that it juxtaposes the principles of the analytical formalism in the form of computer simulations with real experiments. If the topology of objects is known or predetermined by suitable sample preparations, hydrodynamics can be simulated and measured under identical conditions. This option opens a promising application field of utmost importance for chemical engineering. The term fluid dynamics is moreover understood in a generalized sense. Apart from pressure-driven flow, a wealth of related transport phenomena will be addressed in this chapter. The scope covers examples as different as the spatially resolved probing of thermal convection, heat conduction, electroosmosis, and ionic currents.

Rainer Kimmich

Chapter 5. Molecular Dynamics in Polymers

Abstract

Suitably modified versions of the Langevin equation introduced in Chap. 2 will be taken as a general basis for analytical explanations of macromolecular-chain motions. The reader will straightforwardly be led from the dynamics of freely draining polymer chains as the simplest case to entangled-chain phenomena and finally to mesoscopic confinement effects. The Langevin equation-based treatments will be supplemented step by step by additional force terms specific for the diverse model scenarios. The restriction to this equation-of-motion strategy is expected to favor the comprehensibility of this demanding field. The relaxation-mode solutions will be expressed in the form of predictions for diverse experimental techniques outlined in Chap. 3. This in particular refers to spin–lattice relaxation, coherent and incoherent neutron scattering, and mechanical relaxation.

Rainer Kimmich

Chapter 6. Molecular and Collective Dynamics in Liquid Crystals and Other Mesophases

Abstract

In a sense, liquid crystals are strongly related to polymers as concerns molecular dynamics. Analytical treatments on the basis of suitable equations of motions result again in solutions based on collective relaxation modes. The features how order-director fluctuations manifest themselves in NMR relaxation experiments and dynamic light scattering will be figured out in detail. Molecular dynamics in lipid bilayers, often considered as biological model membranes, and other layered structures are further examples belonging to this category. This chapter also addresses less common subjects such as shape fluctuations of vesicles and the consequences of the diffusion of structural defects on dielectric relaxation. Finally, the dynamics in the ordered mesophase of poly(dialkylsiloxane) materials will be examined as a relatively exotic but nevertheless most interesting research area.

Rainer Kimmich

Chapter 7. Dynamics at Fluid Solid Interfaces: Porous Media and Colloidal Particles

Abstract

This chapter could be entitled “molecular motions in complex media” as well. The point is that the systems of interest can be defined by the existence of fluid–solid interfaces. Surface-related phenomena are therefore of central interest. There is an endless list of examples belonging to this category in principle. Emphasis will be laid on porous glasses, fine-particle agglomerates, biopolymer solutions, lipid bilayers, biological tissue, etc. The predominant purpose of this chapter is to elaborate a well-classified scheme of the key mechanisms determining molecular dynamics in the presence of fluid–solid interfaces. This includes adsorption and exchange kinetics, translational and rotational diffusion, and liquid/vapor coexistence phenomena. Effects due to fluid–wall interactions on the one hand and, on the other hand, owing to geometric confinement in mesoscopic pore spaces will thoroughly be discriminated.

Rainer Kimmich

Backmatter

Titel: Principles of Soft-Matter Dynamics
verfasst von: Rainer Kimmich
Verlag: Springer Netherlands
Electronic ISBN: 978-94-007-5536-9
Print ISBN: 978-94-007-5535-2
DOI: https://doi.org/10.1007/978-94-007-5536-9