Cheng Phase Transitions in Polymers: The Role of Metastable States

1. Auflage 2008
ISBN: 978-0-08-055820-2
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 324 Seiten

A classical metastable state possesses a local free energy minimum at infinite sizes, but not a global one. This concept is phase size independent. We have studied a number of experimental results and proposed a new concept that there exists a wide range of metastable states in polymers on different length scales where their metastability is critically determined by the phase size and dimensionality. Metastable states are also observed in phase transformations that are kinetically impeded on the pathway to thermodynamic equilibrium. This was illustrated in structural and morphological investigations of crystallization and mesophase transitions, liquid-liquid phase separation, vitrification and gel formation, as well as combinations of these transformation processes. The phase behaviours in polymers are thus dominated by interlinks of metastable states on different length scales. This concept successfully explains many experimental observations and provides a new way to connect different aspects of polymer physics.
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Autoren/Hrsg.

Cheng, Stephen Z. D.

Inhaltsverzeichnis

1;Cover;1
2;Copyright Page;5
3;TOC$Contents;6
4;Foreword;10
5;Preface and Acknowledgments;14
6;CH$Chapter 1: Introduction;18
6.1;1. Phases in Single-Component Systems;18
6.1.1;1.1. Macroscopic description of phases;18
6.1.2;1.2. Microscopic description of phases;20
6.1.3;1.3. Connection between microscopic descriptions and macroscopic properties;24
6.2;2. Phase Transitions in Single-Component Systems;27
6.2.1;2.1. Definitions of phase transitions;27
6.2.2;2.2. Phase equilibrium and stability;29
6.3;References and Further Reading;31
7;CH$Chapter 2: Thermodynamics and Kinetics of Phase Transitions;34
7.1;1. Thermodynamics of Phase Transitions in Single Component Systems;35
7.1.1;1.1. An example of liquid-gas transitions: van der Waals gas;35
7.1.2;1.2. General descriptions of liquid-gas and crystalline solid-liquid transitions;37
7.1.3;1.3. Crystalline solid-solid transitions;41
7.1.4;1.4. Transitions involving mesophases;42
7.2;2. Kinetic Aspects of Phase Transitions in Single Component Systems;48
7.2.1;2.1. Crystallization;48
7.2.2;2.2. Crystal melting kinetics;52
7.2.3;2.3. Transition kinetics involving mesophases;54
7.3;3. Phases and Phase Transitions in Multiple Component Systems;56
7.3.1;3.1. Gibbs phase rule;56
7.3.2;3.2. General thermodynamics of binary mixing;57
7.3.3;3.3. Liquid-liquid phase separation in binary mixtures;59
7.3.4;3.4. Kinetics of liquid-liquid phase separation in binary mixtures;62
7.3.5;3.5. Crystalline solid-liquid transitions in binary mixtures;68
7.3.6;3.6. Mesophase-liquid transitions in binary mixtures;69
7.4;References and Further Reading;73
8;CH$Chapter 3: Concepts of Metastable States;78
8.1;1. Ostwald's Stage Rule and Definition of a Metastable State;78
8.2;2. Examples of Metastable States in Phase Transitions;80
8.2.1;2.1. Metastable states in liquid-gas transitions;80
8.2.2;2.2. Metastable states in crystalline solid-liquid transitions;82
8.3;3. Appearance of Metastable States Controlled by Competing Kinetics;84
8.4;4. What are the Limitations of the Current Understanding of Metastable States?;88
8.5;5. Concept of Metastability;90
8.6;References and Further Reading;92
9;CH$Chapter 4: Metastable States in Phase Transitions of Polymers;94
9.1;1. Supercooled Liquids and Crystallization;95
9.1.1;1.1. Supercooled liquids;95
9.1.2;1.2. Comments on polymer crystallization theories;98
9.1.3;1.3. Primary nucleation process in polymer crystallization;108
9.1.4;1.4. Structure of the interfacial liquid near the crystal growth front;111
9.1.5;1.5. What is the nucleation barrier?;113
9.2;2. Superheated Crystals and Crystal Melting;123
9.2.1;2.1. Superheated crystals;123
9.2.2;2.2. Irreversible polymer crystal melting;127
9.2.3;2.3. Determining crystal metastability;128
9.2.4;2.4. Ensuring constant metastability during heating;134
9.2.5;2.5. Polymer crystal melting at elevated pressures;137
9.2.6;2.6. Polymer crystal melting kinetics;139
9.3;3. Metastable States in Phase-Separated Polymer Blends and Copolymers;141
9.3.1;3.1. Metastable states in phase-separated polymer blends;141
9.3.2;3.2. Kinetics of liquid-liquid phase separation in polymer blends;144
9.3.3;3.3. Metastable states in phase-separated block copolymers;147
9.3.4;3.4. Polymer crystallization in nano-confined environments using diblock copolymers as templates;153
9.4;References and Further Reading;159
10;CH$Chapter 5: Metastable States Observed Due to Phase Transformation Kinetics in Polymers;174
10.1;1. Appearance of Metastable States Based on Their Crystal Nucleation Barrier;175
10.1.1;1.1. Crystal growth rates along different growth planes;175
10.1.2;1.2. Initial transient state in polymer crystallization;185
10.1.3;1.3. Nucleation and growth rates affected by chain conformation;190
10.2;2. Polymorphs and Competing Formation Kinetics;193
10.2.1;2.1. Phase stability changes in polymorphs at atmospheric pressure;193
10.2.2;2.2. Phase stability changes in polymorphs at high pressures and temperatures;203
10.2.3;2.3. External field-induced polymorphs;210
10.3;3. Monotropic Phase Transitions in Polymers;212
10.3.1;3.1. Crystallization kinetics enhanced by a preordered mesophase;212
10.3.2;3.2. Change of phase transition sequence due to existence of a preordered state;216
10.4;4. Surface- and Interface-Induced Metastable Phases;220
10.4.1;4.1. Surface-induced metastable polymorphs;220
10.4.2;4.2. Metastable states introduced by unbalanced surface stresses caused by chain folding;230
10.5;References and Further Reading;238
11;CH$Chapter 6: Interdependence of Metastable States on Different Length Scales;254
11.1;1. Combining Phase Size Effects with Polymorphs;255
11.1.1;1.1. Phase-stability changes in polymorphs based on phase sizes;255
11.1.2;1.2. Examples of phase inversion by crossing over the phase-stability boundaries;262
11.1.3;1.3. Examples of phase inversion without crossing the phase-stability boundaries;273
11.2;2. Liquid-Liquid Phase Separation Coupled with Vitrification;277
11.3;3. Liquid-Liquid Phase Separation Coupled with Crystallization;283
11.3.1;3.1. Liquid-liquid phase separation intervened by crystallization in solution;283
11.3.2;3.2. Sequential liquid-liquid phase separation and crystallization in solution;287
11.3.3;3.3. Liquid-liquid phase separation intersected by crystallization in polymer blends;291
11.3.4;3.4. Sequential liquid-liquid phase separation and crystallization in polymer blends;298
11.4;4. Liquid-Liquid Phase Separation Associated with Gelation and Crystallization;303
11.5;References and Further Reading;310
12;CH$Chapter 7: Outlook: A Personal View;316
13;IDX$Index;320