Nanostructured Conductive Polymers

Ali Eftekhari is Professor of Chemistry and Director of the Avicenna Institute of Technology in Cleveland (USA). He received his PhD at Trinity College (Ireland). From 2000 to 2002, he was a researcher at Nirvan Co. (USA) working on an environmental project under support of former Vice-President Al Gore. From 2002 to 2004, Professor Eftekhari was senior researcher at KICR (USA), working on a joint corporate project based in United States and Iran. For the next two years, he was Head of the Electrochemistry Division at the Materials and Energy Research Center in Iran. Since 2007, Ali Eftekhari has been Professor of Chemistry and Director of Avicenna Institute of Technology. He is the editor of four books including Nanostructured Materials in Electrochemistry (Wiley) and editor of the book Boltzmann Philosophy of Science. Professor Eftekhari is Editor of the Journal of Nanomaterials and has been chairman or on the Editorial Advisory Boards of several conferences. His research interests include electrochemistry, nanoscience and nanotechnology, statistical physics, condensed matter physics, philosophy, the history of science, management and science policy.

Preface xv

Foreword xix

List of Contributors xxi

Part One 1

1 History of Conductive Polymers 3
J. Campbell Scott

1.1 Introduction 3

1.2 Archeology and Prehistory 7

1.3 The Dawn of the Modern Era 8

1.4 The Materials Revolution 12

1.5 Concluding Remarks 13

Acknowledgments 15

References 15

2 Polyaniline Nanostructures 19
Gordana Ćirić-Marjanović

2.1 Introduction 19

2.2 Preparation 21

2.2.1 Preparation of Polyaniline Nanofibers 21

2.2.2 Preparation of Polyaniline Nanotubes 42

2.2.3 Preparation of Miscellaneous Polyaniline Nanostructures 52

2.3 Structure and Properties 60

2.3.1 Structure and Properties of Polyaniline Nanofibers 60

2.3.2 Structure and Properties of Polyaniline Nanotubes 63

2.4 Processing and Applications 64

2.4.1 Processing 64

2.4.2 Applications 65

2.5 Conclusions and Outlook 74

References 74

3 Nanoscale Inhomogeneity of Conducting-Polymer-Based Materials 99
Alain Pailleret and Oleg Semenikhin

3.1 Introduction: Inhomogeneity and Nanostructured Materials 99

3.2 Direct Local Measurements of Nanoscale Inhomogeneity of Conducting and Semiconducting Polymers 101

3.2.1 Introduction 101

3.2.2 Atomic Force Microscopy (AFM), Kelvin Probe Force Microscopy (KFM), and Electric Force Microscopy (EFM) 103

3.2.3 Current-Sensing Atomic Force Microscopy (CS-AFM) 105

3.2.4 Scanning Tunneling Microscopy (STM) and Scanning Tunneling Spectroscopy (STS) 109

3.2.5 Phase-Imaging Atomic Force Microscopy (PI-AFM) and High-Resolution Transmission Electron Microscopy (HRTEM): Studies of Local Crystallinity 112

3.2.6 Near-Field Scanning Optical Microscopy (NSOM) 124

3.3 In situ Studies of Conducting and Semiconducting Polymers: Electrochemical Atomic Force Microscopy (EC-AFM) and Electrochemical Scanning Tunneling Microscopy (EC-STM) 128

3.3.1 Introduction 128

3.3.2 EC-AFM Investigations of the Swelling/Deswelling of ECPs 129

3.3.3 EC-STM Investigations of the Swelling/Deswelling of ECPs 140

3.3.4 Scanning Electrochemical Microscopy (SECM) Investigations of ECPs 141

3.4 The Origin of the Nanoscale Inhomogeneity of Conducting and Semiconducting Polymers 144

References 151

Part Two 161

4 Nanostructured Conductive Polymers by Electrospinning 163
Ioannis S. Chronakis

4.1 Introduction to Electrospinning Technology 163

4.2 The Electrospinning Processing 164

4.3 Electrospinning Processing Parameters: Control of the Nanofiber Morphology 165

4.3.1 Solution Properties 165

4.3.2 Process Conditions 166

4.3.3 Ambient Conditions 167

4.4 Nanostructured Conductive Polymers by Electrospinning 168

4.4.1 Polyaniline (PANI) 168

4.4.2 Polypyrrole (PPy) 175

4.4.3 Polythiophenes (PThs) 179

4.4.4 Poly(p-phenylene vinylenes) (PPVs) 183

4.4.5 Electrospun Nanofibers from Other Conductive Polymers 186

4.5 Applications of Electrospun Nanostructured Conductive Polymers 187

4.5.1 Biomedical Applications 187

4.5.2 Sensors 194

4.5.3 Conductive Nanofibers in Electric and Electronic Applications 197

4.6 Conclusions 201

References 201

5 Composites Based on Conducting Polymers and Carbon Nanotubes 209
M. Baibarac, I. Baltog, and S. Lefrant

5.1 Introduction 209

5.2 Carbon Nanotubes 212

5.2.1 Synthesis of CNTs: Arc Discharge, Laser Ablation, Chemical Vapor Deposition 214

5.2.2 Purification 217

5.2.3 Separation Techniques for Metallic and Semiconducting Carbon Nanotubes 219

5.2.4 Vibrational Properties of Carbon Nanotubes 222

5.3 Synthesis of Composites Based on Conducting Polymers and Carbon Nanotubes 224

5.3.1 Polyaniline/Carbon Nanotubes 225

5.3.2 Polypyrrole/Carbon Nanotubes 228

5.3.3 Poly(3,4-ethylenedioxythiophene)/Carbon Nanotubes 229

5.3.4 Poly(2,2 0 -bithiophene)/Carbon Nanotubes 229

5.3.5 Poly(N-vinylcarbazole)/Carbon Nanotubes 230

5.3.6 Polyfluorenes/Carbon Nanotubes 231

5.3.7 Poly(p-phenylene) Vinylene/Carbon Nanotubes 231

5.3.8 Polyacetylene/Carbon Nanotubes 232

5.4 Vibrational Properties of Composites Based on Conducting Polymers and Carbon Nanotubes 233

5.4.1 Conducting Polymer/Carbon Nanotube Bilayer Structures 233

5.4.2 Covalently Functionalized Carbon Nanotubes with Conducting Polymers 233

5.4.3 Conducting Polymers Doped with Carbon Nanotubes 244

5.4.4 Noncovalent Functionalization of Carbon Nanotubes with Conducting Polymers 247

5.5 Conclusions 249

Acknowledgments 250

References 250

6 Inorganic-Based Nanocomposites of Conductive Polymers 261
Rabin Bissessur

6.1 Introduction 261

6.2 FeOCl 262

6.3 V 2 O 5 Systems 263

6.4 Vopo 4 .2h 2 O 273

6.5 MoO 3 274

6.6 Layered Phosphates and Phosphonates 277

6.7 Layered Rutiles 279

6.8 Layered perovskites 280

6.9 Layered Titanates 280

6.10 Graphite Oxide 281

6.11 Conclusions 283

Acknowledgements 284

References 284

7 Metallic-Based Nanocomposites of Conductive Polymers 289
Vessela Tsakova

7.1 Introduction 289

7.2 Oxidative Polymerization Combined with Metal-Ion Reduction (One-Pot Synthesis) 290

7.3 Nanocomposite Formation by Means of Pre-Synthesized Metal Nanoparticles 294

7.4 Metal Electrodeposition in Pre-Synthesized CPs 297

7.4.1 Size and Size Distribution of Electrodeposited Metal Particles 305

7.4.2 Spatial Distribution of Electrodeposited Metal Particles 308

7.4.3 Number Density of Electrodeposited Metal Particles 310

7.5 Chemical Reduction of Metal Ions in Pre-Polymerized CP Suspensions or Layers 312

7.5.1 Use of the Polymer Material as Reductant 312

7.5.2 Use of Additional Reductant 320

7.6 Metallic-Based CP Composites for Electrocatalytic and Electroanalytic Applications 321

List of Acronyms 325

References 325

8 Spectroscopy of Nanostructured Conducting Polymers 341
Gustavo M. do Nascimento and Marcelo A. de Souza

8.1 Synthetic Metals 341

8.2 Nanostructured Conducting Polymers 342

8.3 Spectroscopic Techniques 344

8.3.1 Vibronic Techniques (UV-vis-NIR, FTIR, Raman, Resonance Raman) 345

8.3.2 X-Ray Techniques (XANES, EXAFS AND XPS) 346

8.4 Spectroscopy of Nanostructured Conducting Polymers 349

8.4.1 Nanostructured Polyaniline and its Derivates 349

8.4.2 Nanostructured Poly(Pyrrole) 355

8.4.3 Nanostructured Poly(Thiophenes) 358

8.4.4 Nanostructured Poly(Acetylene) and Poly(Diacetylene) and their Derivates 361

8.5 Concluding Remarks 364

Acknowledgements 365

References 365

9 Atomic Force Microscopy Study of Conductive Polymers 375
Edgar Ap. Sanches, Osvaldo N. Oliveira Jr, and Fabio Lima Leite

9.1 Introduction 375

9.2 AFM Fundamentals and Applications 376

9.2.1 Basic Principles 376

9.2.2 Imaging Modes 377

9.2.3 Force Spectroscopy 399

9.3 Concluding Remarks 405

Acknowledgments 406

References 406

10 Single Conducting-Polymer Nanowires 411
Yixuan Chen and Yi Luo

10.1 Introduction 411

10.2 Fabrication of Single Conducting-Polymer Nanowires (CPNWs) 412

10.2.1 Lithographical Methods 412

10.2.2 Scanning-Probe-Based Techniques 418

10.2.3 Template-Guided Growth or Patterning 426

10.2.4 Other Methods 436

10.3 Transport Properties and Electrical Characterization 443

10.3.1 Background 443

10.3.2 Brief Summary of Transport in 3-D CP Materials 444

10.3.3 Conductivity of CP Nanowires, Nanofibers, and Nanotubes 446

10.3.4 Summary 449

10.4 Applications of Single Conducting Polymer Nanowires (CPNWs) 449

10.4.1 CPNW Chemical and Biological Sensors 450

10.4.2 CPNW Field-Effect Transistors 453

10.4.3 CPNW Optoelectronic Devices 455

10.5 Summary and Outlook 460

References 460

11 Conductive Polymer Micro- and Nanocontainers 467
Jiyong Huang and Zhixiang Wei

11.1 Introduction 467

11.2 Structures of Micro- and Nanocontainers 468

11.2.1 Hollow Spheres 468

11.2.2 Tubes 472

11.2.3 Others 474

11.3 Preparation Methods and Formation Mechanisms 478

11.3.1 Hard-Template Method 478

11.3.2 Soft-Template Method 482

11.3.3 Micro- and Nanofabrication Techniques 485

11.4 Properties and Applications of Micro- and Nanocontainers 486

11.4.1 Chemical and Electrical Properties 487

11.4.2 Encapsulation 488

11.4.3 Drug Delivery and Controlled Release 490

11.5 Conclusions 494

References 495

12 Magnetic and Electron Transport Behaviors of Conductive-Polymer Nanocomposites 503
Zhanhu Guo, Suying Wei, David Cocke, and Di Zhang

12.1 Introduction 503

12.2 Magnetic Polymer Nanocomposite Preparation 506

12.2.1 Solution-Based Oxidation Method 506

12.2.2 Electropolymerization Method 507

12.2.3 Two-Step Deposition Method 508

12.2.4 UV-Irradiation Technique 508

12.3 Physicochemical Property Characterization 509

12.4 Microstructure of the Conductive Polymer Nanocomposites 509

12.5 Interaction between the Nanoparticles and the Conductive-Polymer Matrix 510

12.6 Magnetic Properties of Conductive-Polymer Nanocomposites 512

12.7 Electron Transport in Conductive-Polymer Nanocomposites 515

12.8 Giant Magnetoresistance in Conductive-Polymer Nanocomposites 520

12.9 Summary 522

12.9.1 Materials Design Perspective 524

References 524

13 Charge Transfer and Charge Separation in Conjugated Polymer Solar Cells 531
Ian A. Howard, Neil C. Greenham, Agnese Abrusci, Richard H. Friend, and Sebastian Westenhoff

13.1 Introduction 531

13.1.1 Polymer: PCBM Solar Cells 532

13.1.2 Polymer: Polymer Solar Cells 533

13.1.3 Polymer: Inorganic Nanoparticle Solar Cells 534

13.2 Charge Transfer in Conjugated Polymers 534

13.2.1 Excitons as the Primary Photoexcitations 535

13.2.2 Charge Transfer at Semiconductor Heterojunctions 535

13.2.3 Charge Transport 537

13.2.4 Photoinduced Charge Transfer 538

13.2.5 Onsager–Braun Model of Charge-Transfer State Dissociation 540

13.2.6 Charge Formation from High-Lying Singlet States in a Pristine Polymer 541

13.2.7 Field-Assisted Charge Generation in Pristine Materials 541

13.2.8 Charge Generation in Donor: Acceptor Blends 542

13.2.9 Mechanisms of Charge-Transfer State Recombination 544

13.3 Charge Generation and Recombination in Organic Solar Cells with High Open-Circuit Voltages 545

13.3.1 Exciton Ionization at Polymer: Polymer Heterojunctions 546

13.3.2 Photoluminescence from Charge-Transfer States 547

13.3.3 The Nature of the Charge-Transfer States 549

13.3.4 Probing the Major Loss Mechanism in Organic Solar Cells with High Open-Circuit Voltages 550

13.3.5 Geminate Recombination of Interfacial Charge-Transfer States into Triplet Excitons 552

13.3.6 The Exchange Energy of Interfacial Charge-Transfer States in Semiconducting Polymer Blends 555

13.4 Conclusions and Outlook 555

Acknowledgements 556

References 556

Part Three 563

14 Nanostructured Conducting Polymers for (Electro)chemical Sensors 565
Anthony J. Killard

14.1 Introduction 565

14.2 Nanowires and Nanotubes 566

14.3 Nanogaps and Nanojunctions 568

14.4 Nanofibers and Nanocables 570

14.5 Nanofilms 572

14.6 Metallic Nanoparticle/Conducting-Polymer Nanocomposites 574

14.7 Metal-Oxide Nanoparticles/Conducting-Polymer Nanocomposites 575

14.8 Carbon Nanotube Nanocomposites 577

14.9 Nanoparticles 579

14.10 Nanoporous Templates 582

14.11 Application Summaries 583

14.12 Conclusions 593

References 594

15 Nanostructural Aspects of Conducting-Polymer Actuators 599
Paul A. Kilmartin and Jadranka Travas-Sejdic

15.1 Introduction 599

15.2 Mechanisms and Modes of Actuation 600

15.2.1 Ion Movement and Conducting-Polymer Electrochemistry 600

15.2.2 Bilayer and Trilayer Actuators 600

15.2.3 Linear Actuators and the Inclusion of Metal Contacts 602

15.2.4 Out-of-Plane Actuators 603

15.2.5 Effect of Synthesis Conditions 604

15.3 Modelling Mechanical Performance and Developing Device Applications 604

15.3.1 Modelling of Conducting-Polymer Actuation 605

15.3.2 Applications of Conducting-Polymer Actuators 607

15.4 Effect of Morphology and Nanostructure upon Actuation 610

15.4.1 Chain Alignment 610

15.4.2 Anisotropy 612

15.4.3 Porosity 614

15.4.4 Conformational Changes 614

15.5 Solvent and Ion Size Effects to Achieve Higher Actuation 615

15.5.1 Effect of Ion Size 615

15.5.2 Ionic Liquids 616

15.5.3 Ions Producing Large Actuation Strains 617

15.6 Nanostructured Composite Actuators 619

15.6.1 Blends of Two Conducting Polymers 619

15.6.2 Graphite 620

15.6.3 Carbon Nanotubes 620

15.6.4 Hydrogels 621

15.6.5 Other Interpenetrating Networks 621

15.7 Prospects for Nanostructured Conducting-Polymer Actuators 622

References 623

16 Electroactive Conducting Polymers for the Protection of Metals against Corrosion: from Micro- to Nanostructured Films 631
Pierre Camille Lacaze, Jalal Ghilane, Hyacinthe Randriamahazaka and Jean-Christophe Lacroix

16.1 Introduction 631

16.2 Protection Mechanisms Induced by Conducting Polymers 633

16.2.1 Displacement of the Electrochemical Interface 634

16.2.2 Ennobling the Metal Surface 637

16.2.3 Self-healing Effect with Doping Anions as Corrosion Inhibitors 645

16.2.4 Barrier Effect of the Polymer 650

16.3 Conducting-Polymer Coating Techniques for Usual Oxidizable Metals: Performances of Conducting-Polymer-Based Micron-Thick Films for Protection against Corrosion 656

16.3.1 Coatings Consisting of a Conducting Primer Deposited by Electropolymerization 656

16.3.2 Coatings Made from Conducting-Polymer Formulations 662

16.4 Nanostructured Conducting-Polymer Coatings and Anticorrosion Protection 665

16.4.1 Improving ECP Adhesion to Oxidizable Metals 666

16.4.2 Nanostructured Surfaces Displaying Superhydrophobic Properties 667

16.5 Conclusions 671

Acknowledgement 672

References 672

17 Electrocatalysis by Nanostructured Conducting Polymers 681
Shaolin Mu and Ya Zhang

17.1 Introduction 681

17.2 Electrochemical Synthetic Techniques of Nanostructured Conducting Polymers 682

17.2.1 Synthesis by Cyclic Voltammetry 682

17.2.2 Synthesis by Potentiostat 686

17.2.3 Synthesis by Galvanostat 690

17.3 Electrocatalysis at Nanostructured Conducting-Polymer Electrodes 692

17.3.1 Electrocatalysis by Pure Nanostructured Conducting Polymers 692

17.3.2 Electrocatalysis at the Electrodes of Conducting-Polymer Nanocomposites 695

17.4 Conclusion 700

References 701

18 Nanostructured Conductive Polymers as Biomaterials 707
Rylie A. Green, Sungchul Baek, Nigel H. Lovell, and Laura A. Poole-Warren

18.1 Introduction 707

18.2 Biomedical Applications for Conductive Polymers 708

18.2.1 Electrode Coatings 708

18.2.2 Alternate Applications 709

18.3 Polymer Design Considerations 711

18.3.1 Conduction Mechanism 711

18.3.2 Conventional Components 712

18.3.3 Biofunctional Additives 714

18.4 Fabrication of Nanostructured Conductive Polymers 715

18.4.1 Electrodeposition 717

18.4.2 Chemical Synthesis 718

18.4.3 Alternate Processing Techniques 720

18.5 Polymer Characterization 724

18.5.1 Surface Properties 724

18.5.2 Mechanical Properties 725

18.5.3 Electrical Properties 725

18.5.4 Biological Performance 726

18.6 Interfacing with Neural Tissue 727

18.7 Conclusions 728

References 729

19 Nanocomposites of Polymers Made Conductive by Nanofillers 737
Haiping Hong, Dustin Thomas, Mark Horton, Yijiang Lu, Jing Li, Pauline Smith, and Walter Roy

19.1 Introduction 737

19.2 Experimental 742

19.2.1 Materials and Equipment 742

19.2.2 Preparation of Nanocomposite (Nanotube Grease) 745

19.3 Results and Discussion 748

19.3.1 Thermal and Electrical Properties of Nanocomposites (Nanotube Greases) 748

19.3.2 Rheological Investigation of Nanocomposite (Nanotube Grease) 750

19.3.3 Nanocomposites (Nanotube Greases) with Magnetically Sensitive Nanoparticles 754

19.3.4 Electrical Conductivities of Various Nanofillers (Nanotubes) 759

19.4 Conclusion 761

Acknowledgments 761

References 762

Index 765