Carbon Nanotube Science Synthesis, Properties and Applications

Transcription

1 Carbon Nanotube Science Synthesis, Properties and Applications Carbon nanotubes represent one of the most exciting research areas in modern science. These molecular-scale carbon tubes are the stiffest and strongest fibres known, with remarkable electronic properties, and potential applications in medicine, sensing devices and a wide range of other fields. Cutting through the plethora of information available, Carbon Nanotube Science is the most concise, accessible book for the field, presenting the basic knowledge graduates and researchers need to know. Based on the successful Carbon Nanotubes and Related Structures, this new book focuses solely on carbon nanotubes, covering the major advances made in recent years in this rapidly developing field. Chapters focus on electronic properties, chemical and biomolecular functionalization, nanotube composites and nanotube-based probes and sensors. The book begins with a comprehensive and up-to-date discussion of synthesis, purification and processing methods. With its full coverage of the state of the art in this active research field, this book will appeal to researchers in a broad range of disciplines, including nanotechnology, engineering, materials science, chemistry and physics. Peter J F Harris is Manager of the Centre for Advanced Microscopy at the University of Reading, where he is involved in a wide range of projects in both the physical and biological sciences. His personal research interests mainly involve the application of high-resolution TEM to carbon materials. He is a member of the Editorial Advisory Boards both for the Journal of Physics: Condensed Matter and Carbon.

2 Carbon Nanotube Science Synthesis, Properties and Applications PETER J. F. HARRIS University of Reading, UK

3 CAMBRIDGE UNIVERSITY PRESS Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo, Delhi, Tokyo, Mexico City Cambridge University Press The Edinburgh Building, Cambridge CB2 8RU, UK Published in the United States of America by Cambridge University Press, New York Information on this title: / Cambridge University Press 2009 This publication is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published 2009 A catalogue record for this publication is available from the British Library ISBN Hardback ISBN Paperback Cambridge University Press has no responsibility for the persistence or accuracy of URLs for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate. Information regarding prices, travel timetables, and other factual information given in this work is correct at the time of first printing but Cambridge University Press does not guarantee the accuracy of such information thereafter.

4 Preface page xi 1 Introduction Buckminsterfullerene Fullerene-related carbon nanotubes Single- and double-walled nanotubes Catalytically produced carbon nanotubes Who discovered carbon nanotubes? Carbon nanotube research Scope of the book 10 References 11 2 Synthesis I: arc- and laser-vaporization, and heat treatment methods Production of multiwalled nanotubes by arc-evaporation Early work The arc-evaporation technique: further developments Alternatives to graphite Safety considerations for the arc-evaporation method Growth mechanisms of multiwalled nanotubes in the arc General comments Vapour phase growth Liquid phase growth Solid phase growth The crystallization model Production of multiwalled nanotubes by high-temperature heat treatments Production of single-walled nanotubes by arc-evaporation Production of single-walled nanotubes by laser vaporization Growth mechanisms of SWNTs in the arc and laser methods Vapour liquid solid models Solid-state models 34

5 vi 2.7 Arc-evaporation synthesis of double-walled nanotubes Discussion 37 References 38 3 Synthesis II: catalytic chemical vapour deposition and related methods Catalytic synthesis of multiwalled nanotubes: pre-1991 work Catalytic synthesis of multiwalled nanotubes: post-1991 work Growth of aligned MWNTs on substrates Direct spinning of nanotube yarns Growth mechanisms of catalytically produced MWNTs Catalytic synthesis of single-walled nanotubes Conditions required to produce SWNTs Large-scale catalytic synthesis of SWNTs Preparation of SWNT strands Directed growth of SWNTs Synthesis of SWNTs with defined structures Growth mechanisms of catalytically produced SWNTs Vapour liquid solid mechanisms A solid-state mechanism for CVD growth? Catalytic synthesis of double-walled nanotubes Electrochemical synthesis of multiwalled nanotubes Synthesis of MWNTs by heat treatment of metal-doped carbon Discussion 71 References 72 4 Purification and processing Purification of multiwalled tubes MWNTs produced by arc-evaporation Catalytically-produced MWNTs Purification of single-walled tubes Acid treatment and oxidation Functionalization Physical techniques Assessing purity Processing of multiwalled nanotubes Multiwalled nanotube suspensions and assemblies of pure MWNTs Alignment and arrangement of MWNTs Pure MWNT fibres MWNT sheets Breaking and cutting of MWNTs Processing of single-walled tubes Alignment and arrangement of SWNTs Pure SWNT strands 95

6 vii SWNT sheets Length control of SWNTs Separating metallic and semiconducting single-walled nanotubes Selective elimination Dielectrophoresis Selective functionalization Discussion 101 References Structure Bonding in carbon materials The structure of carbon nanotubes: theoretical discussion Vector notation for carbon nanotubes Unit cells of nanotubes Symmetry classification of nanotubes Defects in the hexagonal lattice The layer structure of multiwalled nanotubes Theory of nanotube capping Experimental studies: multiwalled nanotubes produced by arc-evaporation The layer structure: experimental observations Electron diffraction of MWNTs The cross-sectional shape of multiwalled nanotubes MWNT cap structure Elbow connections and branching structures Experimental studies: multiwalled nanotubes produced by catalysis Experimental studies: single-walled nanotubes General features Electron diffraction of SWNTs HRTEM of SWNTs Scanning tunnelling microscope of SWNTs Neutron diffraction Discussion 140 References Physical properties I: electronic Electronic properties of graphite Electronic properties of nanotubes: theory Band structure of single-walled tubes Effect of curvature and of tube tube interactions Electron transport in nanotubes Effect of a magnetic field 153

7 viii 6.3 Electronic properties of nanotubes: experimental measurements Early studies of multiwalled nanotubes Correlation between electronic properties and structure of single-walled nanotubes Quantum conductance Electronic properties of nanotubes in a magnetic field Superconductivity Nanoelectronic devices Diodes Field effect transistors Logic circuits Magnetic properties of nanotubes Nanotube field emitters Conclusions 172 References Physical properties II: mechanical, optical and thermal Mechanical properties of carbon nanotubes Theoretical predictions Experimental observations: multiwalled nanotubes Experimental observations: single-walled nanotubes Optical properties of nanotubes Optical absorption spectroscopy Fluorescence spectroscopy Raman spectroscopy Thermal properties of nanotubes The physical stability of nanotubes Discussion 198 References Chemistry and biology of nanotubes Covalent functionalization Functionalization of nanotube ends and defects Functionalization of sidewalls Non-covalent functionalization Characterizing chemically functionalized nanotubes Biological functionalization Proteins Nucleic acids Toxicity of carbon nanotubes Discussion 220 References 220

8 ix 9 Carbon nanotube composites Preparation of carbon nanotube/polymer composites Solution mixing Melt processing In situ polymerization Effect of nanotubes on polymer structure Properties of carbon nanotube/polymer composites Mechanical properties Electrical properties Carbon nanotube/ceramic composites Carbon nanotube/carbon composites Carbon nanotube/metal composites Discussion 240 References Filled and heterogeneous nanotubes Filling by arc-evaporation Opening and filling of multiwalled nanotubes using chemical methods Early work Opening by treatment with acid Filling opened tubes Filling catalytically-grown multiwalled nanotubes Water in multiwalled nanotubes Filling single- and double-walled nanotubes Filling with inorganic materials Filling with fullerenes: nano-peapods Gases in nanotubes Hydrogen Other gases Heterogeneous nanotubes Boron carbon nitrogen tubes Carbon nitrogen tubes Carbon boron tubes Discussion 268 References Probes and sensors Nanotube tips for atomic force microscopy Preparing nanotube tips: mechanical assembly Preparing nanotube tips: chemical vapour deposition Imaging using nanotube AFM tips Gas sensors 280

9 x 11.3 Biosensors Physical sensors Discussion 285 References Conclusions Highlights of carbon nanotube research Final thoughts 292 References 293 Name Index 296 Subject Index 299

10 Preface This book was originally conceived as a second edition of my earlier work Carbon nanotubes and related structures: new materials for the twenty-first century (Cambridge University Press, 1999). However, the field has expanded rapidly since 1999, and the tale grew in the telling, to the point where I realized I had essentially written a new book. The new title reflects this, as well as the fact that most of the material concerned with related structures has been omitted: the book now focuses almost entirely on carbon nanotubes themselves. As with the first book, I have benefited enormously from the freely given assistance of colleagues from around the world, many of whom have also provided copies of images and preprints. The following list almost certainly fails to include all who have helped me, so I apologize for any omissions. I also stress that any errors which remain in the book are my responsibility alone. I wish to thank: Pulickel Ajayan, Lizzie Brown, Marko Burghard, Hui-Ming Cheng, Hongjie Dai, Walt De Heer, Cees Dekker, Chris Ewels, John Gallop, Jason Hafner, Michael Holzinger, Martin Hulman, Kaili Jiang, Hiromichi Kataura, Ian Kinloch, Ralph Krupke, Alan Lau, Cheol Jin Lee, Jannik Meyer, Geoff Mitchell, Pasha Nikolaev, Henk Postma, Zhifeng Ren, Daniel Resasco, Andrew Rinzler, Milo Shaffer, Wenhui Song, Kazu Suenaga, Sander Tans, Kenneth Teo, Edman Tsang, Daniel Ugarte, Bruce Weisman and Karen Winey. I would also like to thank Cambridge University Press for their encouragement and patience. Most importantly, I want to thank my wife, Elaine, and daughters Katy and Laura for their continuing love and support. Peter Harris, Twyford, November 2008