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Current printing (last digit): 10 9 8 7 6 5 4 3 2 1 PRINTEDINTHE UNITEDSTATES OFAMERICA PREFACE Alittlemorethantenyearshaveelapsedsincepublicationofthefirstpapers describing the fundamentals of scanning electrochemical microscopy (SECM). During this decade, the field of SECM has evolved substantially. The technique has been used in a variety of ways, for example, as an elec- trochemical tool to study heterogeneous and homogeneous reactions, for high-resolutionimagingofthechemicalreactivityandtopographyofvarious interfaces, and for microfabrication. Quantitative theoretical models have been developed for different modes of the SECM operation. The first com- mercial SECM instrument was introduced in 1999. The SECM technique is now used by a number of research groups in many different countries. We think the time has come to publish the first monograph, providing compre- hensive reviews of different aspects of SECM. The first five chapters of this book contain experimental and theoretical background, which is essential for everyone working in this field:principles of SECM measurements (Chapter 1), instrumentation (Chapter 2), prepara- tion of SECM ultramicroelectrodes (Chapter 3), imaging methodologies (Chapter 4), and theory (Chapter 5). Other chapters are dedicatedtospecific applications and are self-contained. Although some knowledge of electro- chemistry and physical chemistry is assumed, the key ideas are discussedat the level suitable for beginning graduate students. Through the addition of submicrometer-scale spatial resolution, SECM greatly increases the capacity of electrochemical techniques to characterize interfaces and measure local kinetics. In this way, it has proved useful for a broad range of interdisciplinary research. Various applications of SECM are discussed in this book, from studies of biological systems, to sensors,to probing reactions at the liquid/liquid interface. Although we did not intend topresentevenabriefsurveyofthosediverseareasofresearch,eachchapter iii iv Preface provides sufficient details to allow a specialist to evaluate the applicability of the SECM methods for solving a specific problem. We hope it will be useful to all interested in learning about this technique and applying it. We would like to thank our students, co-workers, and colleagues who have done so much to develop SECM. The future for this technique, which is unique among scanning probe methods in its quantitative rigor and its ability to study with ease samples in liquid environments, continues to be a bright one. Allen J. Bard Michael V. Mirkin CONTENTS Preface iii Contributors ix 1 INTRODUCTIONAND PRINCIPLES 1 Allen J. Bard I. Background of Scanning Electrochemical Microscopy 1 II. Principles of SECM 2 III. Applications of SECM 9 References 15 2 INSTRUMENTATION 17 David O. Wipf I. Introduction 17 II. Overview of the SECMApparatus 18 III. Commercial SECM Instrument Implementation 42 IV. Tip Position Modulation Instrumentation 44 V. Constant-Current Mode Instrumentation 44 VI. Experimental Difficulties in DataAcquisition 53 VII. Accessory Equipment for SECM 59 Appendix; Suppliers 66 References 71 v vi Contents 3 THE PREPARATION OF TIPS FOR SCANNING ELECTROCHEMICAL MICROSCOPY 75 Fu-Ren F. Fan and Christophe Demaille I. Introduction 75 II. Preparation Techniques 75 III. Nondisk Tips and Tip Shape Characterization 104 References 107 4 SECM IMAGING 111 Fu-Ren F. Fan I. Introduction 111 II. Principle and Methodology of SEM Imaging 111 III. Images in Solutions 115 IV. Images in HumidAir 124 V. Conclusions and Future Projections 139 References 141 5 THEORY 145 Michael V. Mirkin I. Introduction 145 II. Feedback Mode of SECM Operation 145 III. Generation/Collection (G/C) Mode of SECM Operation 165 IV. SECM of More Complicated Chemical Systems 170 V. Numerical Solution of SECM Diffusion Problems Using PDEase2 Program Package 182 List of Symbols 193 References 198 6 HETEROGENEOUS ELECTRON TRANSFER REACTIONS 201 Kai Borgwarth and Ju¨rgen Heinze I. Introduction 201 II. Principles 203 III. Studies of Heterogeneous Electron Transfer 217 IV. Applications 234 V. Conclusion and Outlook 237 References 238 Contents vii 7 KINETICS OF HOMOGENEOUS REACTIONS COUPLED TO HETEROGENEOUS ELECTRON TRANSFER 241 Patrick R. Unwin I. Introduction 241 II. EC Processes 244 i III. EC Processes 270 2i IV. ECE/DISP Processes 283 References 297 8 CHARGE-TRANSFERAT THE LIQUID/LIQUID INTERFACE 299 Michael V. Mirkin and Michael Tsionsky I. Introduction 299 II. Electron Transfer 301 III. Ion Transfer at the ITIES 325 IV. Processes with Coupled Homogeneous Reactions 336 References 339 9 IMAGING MOLECULAR TRANSPORTACROSS MEMBRANES 343 Bradley D. Bath, Henry S. White, and Erik R. Scott I. Introduction 343 II. Principles of Imaging Porous Membranes 346 III. Applications 365 IV. Future Directions 392 References 394 10 POTENTIOMETRIC PROBES 397 Guy Denuault, Ge´za Nagy, and Kla´ra To´th I. Introduction 397 II. Basic Theory 415 III. Properties and Behavior of Ion-Selective Probes 417 IV. Potentiometric Measurements in Scanning Probe Microscopies Other than SECM 422 V. Potentiometric Measurements in SECM 423 VI. Conclusion 441 References 442 viii Contents 11 BIOLOGICAL SYSTEMS 445 Benjamin R. Horrocks and Gunther Wittstock I. Approaches to Imaging Biological and Biochemical Systems 445 II. SelectedApplications 463 III. Conclusion and Outlook 504 IV. Abbreviations,Acronyms, and Symbols 510 References 512 12 PROBING REACTIONSAT SOLID/LIQUID INTERFACES 521 Julie V. Macpherson and Patrick R. Unwin I. Introduction 521 II. Measurement of Adsorption/Desorption Kinetics and Surface Diffusion Rates 523 III. Dissolution Kinetics of Ionic Single Crystals 536 IV. Corrosion Studies 573 V. Conclusions 588 References 590 13 MICRO-AND NANOPATTERNING USING THE SCANNING ELECTROCHEMICALMICROSCOPE 593 Daniel Mandler I. Patterning by the Direct Mode of the SECM 594 II. Patterning by the Feedback Mode of the SECM 603 III. PerspectiveApproaches 623 References 625 14 CONCLUSIONSAND PROSPECTS 629 Allen J. Bard I. Combining SECM with Other Techniques 629 II. Novel Interfaces 634 III. Instrumentation Improvements 636 References 637 Index 639 CONTRIBUTORS ALLEN J. BARD The University of Texas at Austin,Austin, Texas BRADLEY D. BATH ALZACorporation, Mountain View, California KAI BORGWARTH Institute for Physical Chemistry,Albert Ludwig University of Freiburg, Freiburg, Germany CHRISTOPHE DEMAILLE The University of Texas at Austin,Austin, Texas GUY DENUAULT University of Southampton, Southampton, England FU-REN F. FAN The University of Texas at Austin,Austin, Texas JU¨RGEN HEINZE Albert Ludwig University of Freiburg, Freiburg, Germany BENJAMIN R. HORROCKS University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom JULIE V. MACPHERSON University of Warwick, Coventry, England DANIEL MANDLER The Hebrew University of Jerusalem, Jerusalem, Israel MICHAELV. MIRKIN Queens College–City University of New York, Flushing, New York ix