Preface ........................................................ ix
1 Introduction ................................................. 1
1.1 Overview ................................................ 1
1.2 Structure of polymers ................................... 2
1.2.1 Chemical structure - saturated polymers .......... 2
1.2.2 Chemical structure - unsaturated polymers ........ 5
1.2.3 Preparation of polymers .......................... 7
1.2.4 Chemical and physical variants .................. 13
1.2.5 Conformation and hindered rotation .............. 17
1.2.6 Copolymers ...................................... 19
1.2.7 Crystallisation and orientation ................. 19
1.3 Polymers as non-conductive materials ................... 22
1.4 Polymers as conductive materials ....................... 23
1.5 Electrical applications of polymers .................... 24
1.6 Further reading ........................................ 26
2 Dielectrics in static fields ................................ 27
2.1 Electrostatic relations ................................ 27
2.2 Molecular polarisability ............................... 31
2.3 The local field ........................................ 34
2.4 The Clausius-Mosotti relation .......................... 37
2.5 Polar molecules ........................................ 39
2.6 Relative permittivity of polymers ...................... 48
2.6.1 Non-polar polymers .............................. 48
2.6.2 Polar polymers .................................. 49
2.6.3 Mean-square moment .............................. 50
2.7 Low relative permittivity polymers ..................... 52
2.8 Further reading ........................................ 56
3 Dielectric relaxation ....................................... 58
3.1 General theory ......................................... 58
3.1.1 Complex relative permittivity and dielectric
loss ............................................ 58
3.1.2 The dielectric relaxation process ............... 60
3.1.3 Departures from the Debye model ................. 64
3.2 Thermal activation of dipolar relaxation ............... 66
3.3 Cooperative dipolar relaxation in polymers ............. 69
3.4 Dielectric relaxation in solid polymers ................ 72
3.5 Polymer liquids ........................................ 79
3.5.1 Dilute solutions ................................ 79
3.5.2 Concentrated solutions and melts ................ 84
3.6 Interfacial polarisation ............................... 85
3.6.1 M axwell-Wagner effects ......................... 85
3.6.2 Electrode polarisation .......................... 87
3.7 Electronic effects ..................................... 88
3.7.1 Non-linear effects .............................. 94
3.7.2 Molecular non-linearity ......................... 97
3.8 Further reading ....................................... 110
4 Electronic conduction in polymers .......................... 111
4.1 Introduction .......................................... 111
4.2 Theories of electronic conduction ..................... 115
4.2.1 Band theory of conduction ...................... 115
4.2.2 Properties of semiconductors ................... 125
4.2.3 Hopping conduction ............................. 132
4.2.4 The metal-insulator transition ................. 136
4.2.5 Band theory applied to polymers ................ 140
4.2.6 Superconduction ................................ 149
4.3 Further reading ....................................... 152
5 Measurement of electrical properties ....................... 154
5.1 Introduction .......................................... 154
5.2 Bridge methods ........................................ 161
5.3 Resonance methods ..................................... 164
5.4 Frequency response analyser methods ................... 166
5.5 Wave-transmission methods ............................. 169
5.6 Time-domain methods ................................... 173
5.7 Measurement of resistivity ............................ 177
5.8 Further reading ....................................... 185
6 Dielectric breakdown ....................................... 186
6.1 Introduction .......................................... 186
6.2 Electronic breakdown .................................. 187
6.3 Electromechanical breakdown ........................... 192
6.4 Thermal breakdown ..................................... 194
6.5 Breakdown caused by gas discharges .................... 195
6.5.1 Internal discharges and electric treeing ....... 196
6.5.2 External discharges and surface tracking ....... 199
6.6 Long term endurance under electrical stress ........... 201
6.6.1 Endurance experiments .......................... 202
6.6.2 Electrokinetic modelling of dielectric
endurance ...................................... 203
6.6.3 Alternating fields ............................. 208
6.6.4 Water treeing .................................. 209
6.6.5 Effect of space charges ........................ 210
6.7 Examples of high-voltage design ....................... 211
6.7.1 Power cables ................................... 211
6.7.2 Thin-film capacitors ........................... 212
6.8 Further reading ....................................... 214
6.9 Appendix - Breakdown statistics ....................... 214
7 Static charges ............................................. 217
7.1 Introduction .......................................... 217
7.2 Measurement of static charges ......................... 220
7.2.1 Measurement of surface charges ................. 221
7.2.2 Measurement of space charges ................... 227
7.3 Contact charging of polymers .......................... 232
7.3.1 Charge transfer by electrons ................... 232
7.3.2 Charge transfer by ions ........................ 242
7.4 Electrets ............................................. 245
7.5 Further reading ....................................... 249
8 Ionic conduction and particulate and molecular composites .. 250
8.1 Introduction .......................................... 250
8.2 Ionic conduction ...................................... 251
8.2.1 Ionic impurities ............................... 251
8.2.2 Antistatic agents .............................. 257
8.2.3 Polyelectrolytes and protonic conductors ....... 258
8.2.4 Solid polymer electrolytes ..................... 261
8.3 Particulate composites ................................ 266
8.3.1 Conductive powder composites ................... 270
8.3.2 Conductive fibre composites ................... 284
8.4 Molecular composites .................................. 287
8.4.1 Carrier mobility ............................... 290
8.4.2 Photoconductivity .............................. 299
8.4.3 Space charge effects ........................... 302
8.5 Further reading ....................................... 305
9 Intrinsically conductive polymers .......................... 306
9.1 Introduction .......................................... 306
9.2 Conjugated polymers ................................... 307
9.2.1 Preparative methods ............................ 311
9.3 Theories of electronic properties ..................... 322
9.3.1 Doping of conjugated polymers .................. 327
9.3.2 Disordered conjugated polymers ................. 333
9.4 Physical and chemical properties ...................... 340
9.4.1 Morphology ..................................... 341
9.4.2 Intrinsic optical properties ................... 344
9.4.3 Intrinsic electronic properties ................ 359
9.4.4 Doped and metallic polymers .................... 379
9.5 Further reading ....................................... 393
10 Applications of electro-active and conductive polymers ..... 395
10.1 Introduction .......................................... 395
10.2 Electro-active polymers ............................... 395
10.2.1 Xerography ..................................... 395
10.2.2 Organic light emitting diodes and solar cells .. 401
10.2.3 Non-linear optics .............................. 404
10.3 Intrinsically conductive polymers ..................... 412
10.3.1 Soft electronics ............................... 414
10.3.2 Light emitting diodes .......................... 421
10.3.3 Photovoltaic devices ........................... 432
10.3.4 Sensors ........................................ 438
10.3.5 Electrochemical applications ................... 441
10.3.6 Conductive coatings and composites ............. 447
10.3.7 Other applications ............................. 451
10.4 Further reading ....................................... 456
References .................................................... 458
Index ......................................................... 475
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