Chemical Electrostatics (eBook)

Prof. Dr. Fernando Galembeck: Born in São Paulo, Brazil in 1943. Chemistry B.Sc. (1964) and Ph.D. (1970, University of São Paulo - USP), research fellow in the Universities of California and Colorado (1972-4) and in the Unilever Res. Port Sunlight Lab. (1976). Career: USP lecturer to associate professor (1964-1980) and Unicamp (1980-2011), full professor since 1987. Director of the Brazilian National Nanotechnology Laboratory (2011-5), currently Guest Professor at Unicamp. Advised 35 Ph.D. students, published 241 papers, 6 review articles, 50 editorials, edited or authored three books and contributed chapters to six others. Inventor listed in 28 patents that led to 4 products launched in the market. Consultant of product and process development and scientific board member in many funding agencies and companies. Member of the Brazilian Academy of Sciences, TWAS, and Tellesio-Galilei Academy, received many prizes for scientific achievement and innovation, in Brazil, France and US.  Prof. Dr. Thiago A. L. Burgo: received his BSc degree (Chemistry) from the State University of Maringa and his PhD from the University of Campinas (2013), working on the triboelectrification of dielectric polymers, when he identified charge carriers and showed for the first time their effects on friction coefficients. Afterwards, he joined the Argonne National Laboratory (Chicago, USA) as a postdoc, investigating the exchange of electric charge at metal–insulator interfaces during friction force fluctuations. His research interests include scanning probe microscopy, electrostatic adhesion, stream electricity and functional materials. Received two consecutive prizes from Electrostatics Society of America for his works dealing with electrostatics of polymers and friction phenomena related to electric charges.

Dedication 5
Preface 6
Acknowledgements 9
Contents 10
Chapter 1: Living in an Electrified Environment 16
1.1 The Earth Capacitor 16
1.2 The Global Atmospheric Electrical Circuit 17
1.3 Electricity Produced Within the Earth Capacitor 19
1.3.1 Local Current Transients Within the Earth Capacitor: Lightning 19
1.3.1.1 Dry Lightning 20
1.3.1.2 Lightning and Volcanic Activity 20
1.3.1.3 Lightning and Sandstorms 22
1.3.2 Coupling to Earthquakes 22
1.3.3 In Other Planets 22
1.4 Electricity in the Crust: The Self-Potential 23
1.5 Human Perception of Environmental Electricity 23
1.6 Conclusions 24
References 25
Chapter 2: Electroneutrality: When and Where? 27
2.1 A Widespread Belief 27
2.2 Charge Accumulation, Electrostatic Discharge 28
2.3 Electric Potential, Electric Field, Electrochemical Potential 29
2.4 Taking Electroneutrality for Granted 30
2.5 The Electroneutrality Principle 31
2.6 Pauling’s Principle of Electroneutrality 32
2.7 Factors of Non-Electroneutrality 32
2.7.1 Dangling Bonds 32
2.7.2 Are Ionic Crystals Electroneutral? 33
2.7.3 New Ion Sources for Mass Spectrometry 33
2.7.4 Contact Charging, Mechanochemistry, Tribochemistry 34
2.7.5 Liquid Junction Potential and Membrane Potential 35
2.7.6 Electrostatics in Chemical Processing 36
2.7.7 Electrostatics in Soft Matter 36
2.8 Conclusions 37
References 37
Chapter 3: Charge Carriers Within the Atomic-Molecular Theory 41
3.1 Charge and Matter 41
3.1.1 Protons, Electrons, Neutrons, Molecules, and Ions 42
3.1.2 Formation and Stability of Ionic Species 42
3.1.2.1 Ions from Water 43
3.1.3 Electrons 43
3.2 Charge Motion 44
3.2.1 Water 46
3.2.2 Ionic Liquids 46
3.3 Charge Carriers at Interfaces 47
3.3.1 Dimensionality 47
3.3.2 Electrodes and Electrochemistry 48
3.3.3 Electrodes in Capacitors 49
3.3.4 Ion-Exchange Membranes 49
3.3.5 Gas–Liquid and Gas–Solid Interfaces 49
3.3.5.1 Vapor Electricity 49
3.4 Ions, Electrons, or Both? 50
References 51
Chapter 4: Charge at Interfaces 53
4.1 The Maxwell-Wagner-Sillars Effect 53
4.2 Solid–Liquid Interfaces 54
4.2.1 Mechanisms for S/L Interface Charging 54
4.2.2 The Electric Double Layer 55
4.2.3 Experimental Methods 58
4.3 Liquid–Liquid Interfaces 59
4.4 Solid– and Liquid–Gas Interfaces 59
4.4.1 Liquid–Gas Interfaces 60
4.4.1.1 LB Monolayers 60
4.4.1.2 Interfaces of Water and Aqueous Electrolyte Solutions 60
4.4.2 Metal or Semiconductor/Liquid Interfaces 62
4.5 Solid–Solid Interfaces 63
4.5.1 Selective Partition of Adsorbed Ions 63
4.6 Water Structures at Interfaces 64
References 64
Chapter 5: Charge Patterns, Charge Separation 67
5.1 Charge Patterns: From Molecules to Bulk Matter 67
5.2 Charge Separation Within Solids, Liquids and Gases 68
5.2.1 Ionization and Ion Separation 70
5.2.1.1 Solvation 71
5.2.1.2 Dielectric Rupture, Breakdown Voltage 72
5.2.1.3 Ionizing Radiation 72
5.2.1.4 Mechanochemistry, Tribochemistry 73
5.2.2 Charge Segregation 73
5.2.2.1 Differential Mass Transfer 73
5.2.2.2 Sedimentation Potential and Streaming Potential 73
5.2.2.3 Liquid Junction Potential and Membrane Potential 74
5.2.2.4 Self-Assembly 75
5.2.2.5 Supramolecular Structures, Micelle Formation 75
5.3 Pattern Propagation 75
5.4 Stability and Decay Rates of Charge Patterns 76
5.4.1 Systems Under Equilibrium 76
5.4.2 Non-Equilibrium Systems 77
References 77
Chapter 6: Hygroelectricity: The Atmosphere as a Charge Reservoir 79
6.1 Water Vapor Sorption in Solids 79
6.1.1 Water Vapor Adsorption Isotherms 80
6.2 Charging Cellulose Under High Humidity 81
6.3 Charging Metals with Atmospheric Humidity 84
6.4 The Effect of Humidity on Surface Charge Patterns 86
6.4.1 Water Vapor Adsorption and Desorption Modifies Charge Patterns 86
6.4.2 Charge Build-Up on KFM Calibration Samples 91
6.4.3 Excess Charge Decay Through the Atmosphere 93
6.5 Flow Electrification: The Position of Water in the Triboelectric Series 96
6.6 Water Dropping from a Biased Needle 97
6.7 Spontaneous Electric-Bipolar Nature of Aerosols 100
6.8 Conclusion and Prospects 102
References 103
Chapter 7: Excess Charge in Solids: Electrets 105
7.1 Charge in Surfaces and in Bulk Solids 105
7.2 Relevant Features of Solid Surfaces 106
7.2.1 Glass and Other Hydrophilic Surfaces 106
7.2.2 Polyethylene and Other Hydrophobic Solids 108
7.3 Charge Trapping During the Formation of Solids 109
7.4 Electrets 110
7.4.1 Thermally Stimulated Discharge 111
7.4.2 Bioelectrets 112
7.5 Charging Mechanisms 112
7.5.1 Unintended Charging of Solids, Following Mechanical Action and Radiation 112
7.5.2 Charging with Corona 113
7.5.3 Direct Charge Injection from Electrodes 113
7.5.4 Electron, Ion and Photon Beams 114
7.5.5 Electrification by the Liquid Contact Method 114
7.6 Charge Migration from Charged Solids 116
7.7 The Costa Ribeiro (Thermo-Dielectric) Effect 118
7.8 Conclusion 118
References 119
Chapter 8: Friction and Electrostatics 121
8.1 Introduction 121
8.1.1 Adhesive Contact Models: JKR, DMT and Maugis 122
8.2 From Macro to Nanoscale 125
8.3 Electrostatic Contribution to Friction 126
8.3.1 Macro Experiments Relating Surface Charge and Friction Coefficients 127
8.3.2 AFM Experiments (LFM, Force-Distance and Nanomechanical Mode) 132
8.4 Conclusions 135
References 135
Chapter 9: Electrostatic Adhesion 138
9.1 Contact Charging and Electrostatic Adhesion 138
9.2 Electrostatic Adhesion in Soft Materials 139
9.2.1 Rubber and Other Latexes 140
9.2.2 Layer-by-Layer Fabrication 140
9.2.3 “Saltation” and Dust Adhesion 141
9.3 Microchemical Evidence for Electrostatic Adhesion in Materials 141
9.4 Theoretical Estimates 147
9.4.1 Gecko Adhesion 148
9.4.2 Bacterial and Cell Adhesion 149
9.4.3 Biomolecules 151
9.5 Electroadhesion 151
9.6 A Valuable Tool for “Green” Fabrication 152
References 152
Chapter 10: Self-assembly 155
10.1 From Disorder to Order 155
10.1.1 Structure Formation: Thermodynamics and Kinetics 158
10.2 Range and Specificity of Electrostatic Forces 159
10.3 Biological Systems 159
10.4 Ionic Surfactants and Polyelectrolytes 161
10.5 Colloidal Crystals, Macrocrystals and Co-crystals 161
10.6 Micro- and Nano-fabrication Through Electrostatic Self-assembly 162
10.6.1 Microfabrication Coupled to Microfluidics 164
10.7 Conclusions 165
References 166
Chapter 11: Tribogenerators 168
11.1 Introduction 168
11.1.1 Particle Accelerators: Van De Graaff and Pelletron Generators 170
11.2 Energy Harvesting and Scavenging 170
11.3 A New Age for Electrostatic Generators 172
11.3.1 Nanostructured Electrostatic Generators 174
11.4 Some Fundamental Aspects of Tribogenerators 176
References 177
Chapter 12: Accidents and Losses Caused by Electrostatic Discharge 180
12.1 Electrostatic Discharge in Contacting Points 181
12.2 Electrical Discharge in the Electronics Industry 182
12.2.1 Role of the Human Body 183
12.2.2 ESD and RF Devices 184
12.3 ESD in Lighting Equipment 184
12.4 Crushing and Milling 184
12.5 Failure of Home, Office and Field Personal Equipment 184
12.6 Electrostatic Charge Ignition 185
12.6.1 Dust Explosions 186
12.6.2 Electrostatic Charging Associated with Liquid Leakage 188
12.7 Protection Against Electrostatic Discharge 188
12.7.1 New Materials for Avoiding Electrostatic Discharge 188
12.7.1.1 Textiles 188
12.7.1.2 Carbon Nanotubes and Graphene 189
12.7.2 Devices and Equipment: Corona Electrodes 190
12.8 Safety Codes 190
12.9 Electrostatics and Chaos 191
12.10 Final Comments 191
References 192
Chapter 13: Electrostatic Processes and Products 195
13.1 Industrial Applications of Electrostatics 195
13.2 Imaging Technologies 196
13.2.1 Electrophotography or Xerography, Laser Printers 196
13.2.2 Ink-Jet Printers 197
13.2.3 Electrostatic Screen-Printing 197
13.2.4 Electronic Paper 198
13.3 Electrostatic Coating 198
13.4 Electrowetting 200
13.5 Electrostatic Precipitation 202
13.6 Solar Panel Cleaning 203
13.7 Electrostatic Separation 204
13.7.1 Waste Separation 204
13.7.2 Biomass Separation 204
13.7.3 Electrosorption and Capacitive Deionization 205
13.7.4 Metal Recovery from Electronic Equipment 207
13.8 Electroadhesion 207
13.9 Conclusion 209
References 209
Chapter 14: Instrumentation 212
14.1 Measuring Charge, Potential, and Field 212
14.1.1 Comparative Advantages of Charge Detection 214
14.2 Charge Measurement and the Faraday Cup 215
14.2.1 Faraday Cups and Hygroelectricity 217
14.3 Electric Potential: The Kelvin Probe 217
14.3.1 New Developments 219
14.4 Commercially Available Equipment 219
14.5 Apparatus for Specific Measurements 220
14.6 Conclusion 223
References 223
Chapter 15: Perspectives 225
15.1 Current Situation 225
15.2 Fast-Moving Topics 227
15.2.1 Scavenging Energy from the Environment 228
15.2.2 Energy Scavenging and Human Health Care 228
15.3 New Perspectives 228
15.3.1 Electrostatics, Chaos and Disaster Prevention 228
15.3.2 Electrophysiology and Electrotherapy 229
15.3.3 X-Ray Sources 229
15.4 Dissemination 229
References 230
Index 232