Table of Contents
1 Overview of Polyimide Dielectrics 1
Mengyu Xiao and Jun-Wei Zha 1.1 Introduction 1
1.2 Structure Design of Polyimide 1
1.3 Fabrication of Polyimide 4
1.4 Applications of Polyimide 4
1.4.1 Capacitive Energy Storage 4
1.4.2 Electronic Devices 5
1.4.3 Electrical Engineering 6
1.4.4 Medical Materials 6
1.4.5 Environmental Protection 6
1.5 Summary and Outlook 6
References 7
2 Structures and Properties of Polyimide Dielectric Materials 9
Lei Zhai, Yi-Kai Wang, and Lin Fan
2.1 Introducing Polar Groups 10
2.1.1 Nitrile Group 10
2.1.2 Sulfonyl Group 15
2.1.3 Carboxylic Group 18
2.1.4 Pyridine and Urea Group 21
2.2 Introducing Non-Conjugated Structures 21
2.2.1 Aliphatic Structure 22
2.2.2 Cycloaliphatic Structure 25
2.3 Introducing Non-Coplanar Structures 28
2.3.1 Bulky Substituents 28
2.3.2 Spiro Structures 31
2.4 Introducing Crosslinking Structures 34
2.5 Summary and Outlook 38
References 42
3 Processing Technology of Polyimide Dielectrics: From Experimental to Industrial Scale 47
xi Ren, Zhibin He, Shunqi Yuan, Zhenzhong Wang, Shujun Han, Yuexin Qi, and Jingang Liu
3.1 Introduction 47
3.2 PID Synthetic Chemistry 49
3.3 Processing Technologies for PIDs 53
3.3.1 PI Precursor Varnishes 53
3.3.2 PI Film Dielectrics 55
3.3.2.1 PI Films 55
3.3.2.2 PI Nanodielectric Films 58
3.3.3 Thermoplastic PI Dielectrics 61
3.3.4 PI Aerogel Dielectrics 65
3.4 Summary 67
Acknowledgments 68
Declarations 68
References 69
4 Polyimide Dielectrics for High-Temperature Energy Storage 77
Wenjie Huang, Wenshuai Zhao, and Jun-Wei Zha
4.1 Introduction 77
4.2 Key Characteristics and Mechanisms of Polyimide Dielectrics for Energy Storage 79
4.2.1 Dielectric Energy Storage Mechanism 79
4.2.2 Electrical Polarization and Dielectric Permittivity 80
4.2.3 Dielectric Breakdown Strength 81
4.2.4 Dielectric Loss 83
4.2.5 Breakdown Self-Healing Mechanism 85
4.3 Intrinsic Polyimide Dielectrics 86
4.3.1 Dipolar Glass Polyimide Dielectrics 86
4.3.2 Wide Bandgap Polyimide Dielectrics 87
4.4 All-Organic Polyimide Composite Dielectrics 89
4.4.1 Blended Polyimide-Based Composite Dielectrics 90
4.4.2 Polyimide-Based Composite Dielectrics Doped with Organic Semiconductors 90
4.4.3 All-Organic Multilayer Polyimide-Based Composite Dielectrics 90
4.5 Polyimide-Based Nanocomposite Dielectrics 92
4.5.1 Polyimide-Based Composite Dielectrics Doped with Nanofillers 92
4.5.2 Multilayer Polyimide-Based Nanocomposite Dielectrics 94
4.6 Self-Healing Polyimide Dielectrics 95
4.7 Conclusion and Perspective 96
References 98
5 Polyimide Dielectrics with Low Dielectric Permittivity 105
Xiaodi Dong and Jun-Wei Zha
5.1 Fundamental Principles for Low Dielectric Permittivity (Low-k) 105
5.2 Intrinsic Low-k PI 106
5.2.1 Introduction of Fluorinated Structures 107
5.2.2 Introduction of Alicyclic Rings or Steric Rigid Structures 107
5.2.3 Introduction of Other Special Structures 109
5.3 Low-k PI Composites 111
5.3.1 Introduction of Inorganic Functional Filler 111
5.3.2 Introduction of Organic Functional Fillers 113
5.4 Porous Low-k PIs 113
5.4.1 Phase-separation-induced Pores 114
5.4.2 Physically or Chemically Induced Pores 114
5.4.3 Introduction of Porous Fillers 115
5.4.3.1 Porous Inorganic Fillers 115
5.4.3.2 Porous Organic Fillers 117
5.4.3.3 PI Aerogel 118
5.5 Multifunctional Low-k PIs 120
5.6 Conclusion and Prospects 122
References 123
6 High Thermally Conductive Polyimide Dielectrics 133
Fan Wang, Gengbo Liu, and Jun-Wei Zha
6.1 Introduction 133
6.2 Intrinsic Thermally Conductive Polyimide 134
6.2.1 Molecular Chain Structure 135
6.2.2 Molecular Chain Orientation 137
6.2.3 Intermolecular Interaction 139
6.3 Filled Thermally Conductive Polyimide 140
6.3.1 Thermal Conductivity Mechanism of Polymer Composites 140
6.3.2 Effective Strategies for Improving Thermal Conductivity of Polyimide 141
6.3.2.1 Directional Structure Design 141
6.3.2.2 Non-directional Structural Design 144
6.3.2.3 Multi-Layer Structure Design 148
6.4 Multifunctionalization of Thermally Conductive Polyimides 151
6.4.1 Thermal Conductivity and EMI Shielding 151
6.4.2 Thermal Conductivity and Electrical Insulation 153
6.4.3 Thermal Conductivity and Low Permittivity 154
6.5 Conclusions and Outlook 155
References 156
7 Polyimide Nanocomposites for Electromagnetic Interference Shielding 163
Yuchao li
7.1 Introduction 163
7.2 Theoretical 164
7.3 Nanofillers Used for PI Electromagnetic Shielding 168
7.3.1 Magnetic Fillers 168
7.3.2 Metals 169
7.3.3 MXene 170
7.3.4 Graphene 171
7.3.5 Carbon Nanotube 172
7.3.6 Other Fillers 173
7.4 Ternary Composites 174
7.4.1 PI/Conductive Components/Magnetic NPs 174
7.4.2 PI/Conductive Components with Diverse Dimensions 177
7.5 Structural Design 183
7.5.1 Metallized PI Fibric 183
7.5.2 Aerogel 183
7.5.3 Foam 184
7.5.4 Sandwich and Multilayer Film Structure 185
7.5.5 Anisotropic Structure 187
7.5.6 Gradient Conductive Structure 188
7.5.7 Other Structure 189
7.6 Future Development and Prospects 190
7.6.1 Ultralight, Ultrathin, and Ultraflexible 190
7.6.2 High Durability 191
7.6.3 Multifunctional EMI PI 191
7.6.4 Extreme Conditions 192
7.6.5 Recoverable or Shape Memory EMI PI 192
7.6.6 The Next 6G Technology 193
7.7 Summary 193
References 194
8 Colorless Transparent Polyimides with Balanced Dielectric and Optical Properties 203
Xiaojie He and Qinghua Lu
8.1 Introduction 203
8.2 Synthesis and Molecular Structure Design of PIs 204
8.3 Characterization and Evaluation of Properties 205
8.4 Advanced Design Strategies for Fabricating High-Transparency Low-Dielectric PIs 206
8.4.1 Introduction of Fluorine Functional Groups 207
8.4.2 Monomers Containing Cycloaliphatic Structures 211
8.4.3 Monomers with Bulky and Pendant Substituents 214
8.4.4 Monomers with Non-coplanar Structures 216
8.4.5 The Influence of Silicon-Based Particles 218
8.4.6 Porous and Composite Structures in PIs 222
8.4.7 Polyimide Research Driven by Molecular Simulation and Data Science 223
8.5 Summary and Outlook 226
References 227
9 Polyimide Dielectrics in Extreme Environment 237
Yuhuai Wang and Jin li
9.1 Atomic Oxygen Erosion Mechanism of Polyimide 238
9.1.1 Atomic Oxygen Formation and Characteristics 238
9.1.2 Atomic Oxygen Erosion Mechanism of Polyimide 238
9.2 Atomic Oxygen Protection Technology for Polyimide 240
9.2.1 Material Modification Protection 241
9.2.2 Surface Protection 242
9.3 Example of Atomic Oxygen Erosion Protection 243
9.3.1 Example of Protection Against Atomic Oxygen Erosion on the International Space Station (ISS) 243
9.3.2 Example of Protection Against Atomic Oxygen Erosion in the Core Module of the Chinese Space Station Tianhe 243
9.4 Summary 244
References 245
10 Smart Polyimide Dielectrics 247
Deyan Kong, Yu Kang, Shuting Jiang, Hongxia Xie, Pengjie Wu, Ying Jiang, Yueheng Qiao, and Xinli Xiao
10.1 Introduction 247
10.2 Shape Memory Polymer 248
10.2.1 Introduction of Shape Memory Polymer 248
10.2.2 The Shape Memory Molecular Mechanism 249
10.2.3 Shape Memory Performance Test 250
10.3 Heat-driven SMPI 251
10.4 Remote-driven SMPI 253
10.4.1 Electrical-driven SMPI 253
10.4.2 Optically-driven SMPI 254
10.5 Self-healing Polyimide 256
10.5.1 Introduction of Self-healing 256
10.5.2 Development Status of Self-healing Polyimide 259
10.5.2.1 External Self-healing Polyimide 259
10.5.2.2 Intrinsic Self-healing Polyimide 261
10.6 SMPI-based Flexible Optical/Electronic Devices 263
10.7 Smart Polyimide Foam 265
10.7.1 Electromagnetic Interference Shielding Performance of Polyimide-Based Foams 267
10.7.2 Sensing Performance of Polyimide-Based Foams 268
10.8 Atomic-Oxygen-Resistant Polyimide Films with Shape Memory Function 269
10.8.1 Mechanism of Atomic Oxygen Formation and Its Role in Polymers 270
10.8.2 Atomic Oxygen Resistance Modification of Polyimide 271
10.8.2.1 Surface Modification Techniques 272
10.8.2.2 Bulk Phase Modification Techniques 272
References 275
Index 279
