碳纳米管综述

Chemistry of Carbon Nanotubes

Dimitrios Tasis,*,†Nikos Tagmatarchis,‡Alberto Bianco,§and Maurizio Prato*,| Department of Materials Science,University of Patras,26504Rio Patras,Greece,Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation,48Vass.Constantinou Avenue,11635Athens,Greece,Institut de Biologie Mole´culaire et Cellulaire, UPR9021CNRS,Immunologie et Chimie The´rapeutiques,67084Strasbourg,France,and Dipartimento di Scienze Farmaceutiche,

Universita`di Trieste,Piazzale Europa1,34127Trieste,Italy

Received July12,2005

Contents

1.Introduction1105

2.Covalent Approaches1105

2.1.Sidewall Halogenation of CNT1105

2.2.Hydrogenation1107

2.3.Cycloadditions1107

2.4.Radical Additions1109

2.5.Electrophilic Additions1111

2.6.Addition of Inorganic Compounds1111

2.7.Ozonolysis1111

2.8.Mechanochemical Functionalizations1111

2.9.Plasma Activation1112

2.10.Nucleophilic Additions1112

2.11.Grafting of Polymers1112

2.11.1.“Grafting to”Method1112

2.11.2.“Grafting from”Method1112

3.Defect Site Chemistry1113

3.1.Amidation/Esterification Reactions1113

3.2.Attachment of Biomolecules1115

3.3.Grafting of Polymers to Oxidized Nanotubes1116

4.Noncovalent Interactions1117

4.1.Polymer Composites1117

4.1.1.Epoxy Composites1117

4.1.2.Acrylates1118

4.1.3.Hydrocarbon Polymers1119

4.1.4.Conjugated Polymers1119

4.1.

5.Other Nanotube−Polymer Composites1120

4.2.Interactions with Biomolecules and Cells1122

5.Endohedral Filling1125

5.1.Encapsulation of Fullerene Derivatives and

Inorganic Species

1125

5.2.Encapsulation of Biomolecules1126

5.3.Encapsulation of Liquids1127

6.Concluding Remarks1127

7.Acknowledgments1127

8.References1127 1.Introduction

The unidirectional growth of materials to form nanowires or nanotubes has attracted enormous interest in recent years.Within the different classes of tubes made of organic or inorganic materials and exhibiting interesting electronic, mechanical,and structural properties,carbon nanotubes (CNT)are extremely promising for applications in materials science and medicinal chemistry.The discovery of CNT has immediately followed the synthesis of fullerenes in macro-scopic quantities,1and since then the research in this exciting field has been in continuous evolution.2CNT consist of graphitic sheets,which have been rolled up into a cylindrical shape.The length of CNT is in the size of micrometers with diameters up T form bundles,which are entangled together in the solid state giving rise to a highly complex network.Depending on the arrangement of the hexagon rings along the tubular surface,CNT can be metallic or semiconducting.Because of their extraordinary properties, CNT can be considered as attractive candidates in diverse nanotechnological applications,such as fillers in polymer matrixes,molecular tanks,(bio)sensors,and many others.3 However,the lack of solubility and the difficult manipula-tion in any solvents have imposed great limitations to the use of CNT.Indeed,as-produced CNT are insoluble in all organic solvents and aqueous solutions.They can be dispersed in some solvents by sonication,but precipitation immediately occurs when this process is interrupted.On the other hand,it has been demonstrated that CNT can interact with different classes of compounds.4-20The formation of supramolecular complexes allows a better processing of CNT toward the fabrication of innovative nanodevices.In addition, CNT can undergo chemical reactions that make them more soluble for their integration into inorganic,organic,and biological systems.

The main approaches for the modification of these quasi one-dimensional structures can be grouped into three cat-egories:(a)the covalent attachment of chemical groups through reactions onto theπ-conjugated skeleton of CNT;

(b)the noncovalent adsorption or wrapping of various functional molecules;and(c)the endohedral filling of their inner empty cavity.

As clearly visible from the high number of citations,this field is rapidly expanding.The information reported in this review on each literature citation will necessarily be limited in space.It is the aim of this review to consider the three approaches to chemical functionalization of CNT and to account for the advances that have been produced so far.

2.Covalent Approaches

2.1.Sidewall Halogenation of CNT

CNT grown by the arc-discharge or laser ablation methods have been fluorinated by elemental fluorine in the range

†Department of Materials Science,26504Rio Patras,Greece.Telephone: +302610969929.Fax:+302610969368.E-mail:dtassis@upatras.gr.‡Theoretical and Physical Chemistry Institute.

§Institut de Biologie Mole´culaire et Cellulaire.

|Universita`di Trieste.Fax:+390405587883.E-mail:prato@units.it.1105

Chem.Rev.2006,106,1105−1136

10.1021/cr050569o CCC:$59.00©2006American Chemical Society

Published on Web02/23/2006