Nanoparticles – Nanocomposites Nanomaterials: An Introduction for Beginners

Meeting the demand for a readily understandable introduction to nanomaterials and nanotechnology, this textbook specifically addresses the needs of students – and engineers – who need to get the gist of nanoscale phenomena in materials without having to delve too deeply into the physical and chemical details. The book begins with an overview of the consequences of small particle size, such as the growing importance of surface effects, and covers successful, field–tested synthesis techniques of nanomaterials. The largest part of the book is devoted to the particular magnetic, optical, electrical and mechanical properties of materials at the nanoscale, leading on to emerging and already commercialized applications, such as nanofluids in magnetic resonance imaging, high–performance nanocomposites and carbon nanotube–based electronics. Based on the author′s experience in teaching nanomaterials courses and adapted, in style and level, for students with only limited background knowledge, the textbook includes further reading, as well as information boxes that can be skipped upon first reading.

Preface IX 1 Introduction 1 2 Nanoparticles – Nanocomposites 7 2.1 Nanoparticles 7 2.2 Elementary Consequences of Small Particle Size 13 2.2.1 Surface of Nanoparticles 13 2.2.2 Thermal Phenomena 15 2.2.3 Diffusion Scaling Law 17 References 20 3 Surfaces in Nanomaterials 21 3.1 General Considerations 21 3.2 Surface Energy 23 3.3 Vapor Pressure of Small Particles 30 3.4 Hypothetical Nanomotors Driven by Surface Energy 35 References 38 4 Gas–Phase Synthesis of Nanoparticles 39 4.1 Fundamental Considerations 39 4.2 Inert–Gas Condensation Process 47 4.3 Physical and Chemical Vapor Synthesis Processes 48 4.4 Laser–Ablation Process 52 4.5 Plasma Processes 55 4.5.1 Microwave Plasma Processes 55 4.5.2 RF and DC Plasma Processes 63 4.6 Flame Processes 67 4.7 Synthesis of Coated Particles 72 References 76 5 One– and Two–Dimensional Nanoparticles 79 5.1 Basic Considerations 79 5.2 Vibrations of Nanorods and Nanotubes – Scaling Law for Vibrations 88 5.3 Nanostructures Related to Compounds with Layered Structures 89 5.3.1 Carbon– and Boron–Nitride–Based Nanoparticles 89 5.3.2 Nanotubes, Nanorods, and Nanoplates from Materials other than Carbon 97 5.3.3 Polymer Composites Filled with Defoliated Phyllosilicates 101 5.3.4 Synthesis of Nanotubes, Nanorods, and Fullerenes 102 References 110 6 Nanofluids 111 6.1 Background 111 6.2 Nanofluids for Improved Heat Transfer 111 6.3 Ferrofluids 113 6.3.1 Properties of Ferrofluids 113 6.3.2 Applications of Ferrofluids 117 References 119 7 Thermodynamics of Nanoparticles and Phase Transformations 121 7.1 Basic Considerations 121 7.2 Influence of the Particle Size on Thermodynamic Properties and Phase Transformations 121 7.3 Thermal Instabilities Connected to Phase Transformations 132 7.4 Heat Capacity of Nanoparticles 141 References 144 8 Magnetic Nanomaterials, Superparamagnetism 147 8.1 Magnetic Materials 147 8.2 Fundamentals of Superparamagnetism 152 8.3 Susceptibility of Superparamagnetic Materials 162 8.4 Superparamagnetic Particles in the Mößbauer Spectrum 163 8.5 Applications of Superparamagnetic Materials 168 8.6 Exchange–Coupled Magnetic Nanoparticles 173 References 178 9 Optical Properties 181 9.1 General Remarks 181 9.2 Adjustment of the Index of Refraction and Visually Transparent UV Absorbers 181 9.3 Size–Dependent Optical Properties – Quantum Confi nement 184 9.4 Semiconducting Particles in the Quantum–Confinement Range 189 9.5 Metallic Nanoparticles – Plasmon Resonance 197 9.6 Luminescent Nanocomposites 200 9.7 Selection of a Lumophore or Absorber 213 9.8 Electroluminescence 215 9.9 Photochromic and Electrochromic Materials 219 9.9.1 General Considerations 219 9.9.2 Photochromic Materials 220 9.9.3 Electrochromic Materials 222 9.10 Magneto–Optic Applications 224 References 227 10 Electrical Properties 229 10.1 Fundamentals of Electric Conductivity; Diffusive versus Ballistic Conductivity 229 10.2 Carbon Nanotubes 235 10.3 Other One–Dimensional Electrical Conductors 239 10.4 Electrical Conductivity of Nanocomposites 241 References 248 11 Mechanical Properties 249 11.1 General Considerations 249 11.2 Mechanical Properties of Bulk Nanocrystalline Materials 251 11.3 Deformation Mechanisms of Nanocrystalline Materials 255 11.4 Superplasticity 263 11.5 Filled Polymer Composites 265 11.5.1 General Considerations 265 11.5.2 Particle–Filled Polymers 268 11.5.3 Polymer–Based Nanocomposites Filled with Silicate Platelets 269 11.5.4 Carbon–Nanotube– and Graphene–Filled Composites 274 References 278 12 Characterization of Nanomaterials 279 12.1 Specific Surface Area 279 12.2 Analysis of the Crystalline Structure 282 12.3 Electron Microscopy 287 12.3.1 General Considerations 287 12.3.2 Setup of Electron Microscopes 290 12.3.3 Interaction of the Electron Beam with the Specimen 292 12.3.4 Some Examples of Transmission Electron Microscopy 297 12.3.5 High–Resolution Scanning Electron Microscopy 300 References 303 Index 305

Professor Dieter Vollath has more than 20 years experience in the research of synthesis and properties of nanomaterials. He was Department Head at the Forschungszentrum Karlsruhe, Germany, and gives lectures at the Technical University Graz, Austria. Since 2003 he is acting as nanotechnology consultant with his own company NanoConsulting. His courses on nanomaterials formed the basis for this textbook.