Introduction to Nanoscience and Nanomaterials

The following sections are included:

• Preface

• Acknowledgments

• Contents

A nanometer (nm) is one billionth (10⁻⁹) of a meter. Nanoscience can be defined as the science of objects and phenomena occurring at the scale of 1 to 100 nm. The range of 1–100 nm was taken as the defining range by the US National Science and Technology Council in its report titled “National Nanotechnological Initiative: Leading to the Next Industrial Revolution”, in February 2000 and a subsequent report in 2004. The committee noted that “Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable novel applications. ‥‥At this level, the physical, chemical, and biological properties of materials differ in fundamental and valuable ways from the properties of individual atoms and molecules of bulk matter” [1]. It was also mentioned that “novel and differentiating properties and functions are developed at a critical length scale of matter typically under 100 nm”. Actually, in most cases, this happens below 10 nm. On the other hand, some nanoscale phenomena extend beyond 100 nm. The range of 1 to 100 nm appears therefore to be appropriate for the purpose of defining the field as long as it is kept in mind that in some cases one may have to step across these boundaries…

The following sections are included:

• Introduction

• The solid–vapor interface
  • Surface energy
  • Equilibrium shape of a crystal
  • Structure of nanoclusters
    • Icosahedron (Ih)
    • Decahedron (Dh)
  • Surface reconstruction and surface relaxation
    • Surface relaxation
    • Surface reconstruction
    • Reconstructed surfaces as templates for nanostructures
  • Surface defects and crystal defects
    • Defects on the vicinal surfaces
    • Crystal defects
  • Effect of surface curvature
    • Chemical potential at the curved surfaces
    • Pressure under a curved surface
    • Vapor pressure over a curved surface
    • Vacancy concentration under a curved surface
    • Solubility of curved surfaces
  • Examples and applications
    • Melting point of nanoparticles
    • Coarsening of particles — the Ostwald ripening
    • Sintering of solids
    • Condensation of vapor in a capillary: agglomeration of nanoparticles due to pendular forces

• The solid–liquid interface
  • The surface tension
  • The contact angle
  • The contact angle hysteresis
  • Superhydrophobic, superhydrophilic and self cleaning surfaces
    • Increase in contact angle on rough hydrophobic surfaces: the “lotus effect”
    • The Wenzel and the Cassie–Baxter equations
    • Superhydrophilic surfaces: Enhanced hydrophilicity due to surface roughness
    • Examples of superhydrophobic and superhydrophilic surfaces by nanostructuring
    • Titania coated superhydrophilic and self cleaning surfaces

• Appendix 2.1 : Melting point of nanoparticles

• Problems

The following sections are included:

• Introduction

• Size dependence of properties in the nanometer range

• Review of some topics in physics
  • Particle and wave: The Schrodinger equation
    • The hydrogen atom
    • A free particle
    • Particle in an infinite potential square well
  • Free electron model of a solid
  • Electron in a periodic potential: the occurrence of the band gap
  • Reciprocal lattice and the Brillouin zone
    • The reciprocal lattice
    • The Brillouin zones
  • The band structures of semiconductors
  • Energy levels within the band gap – shallow traps and the deep traps
    • Shallow traps in doped semiconductors
    • Deep level traps
  • Characteristic lengths in the nanometer range
    • de Broglie Wavelength
    • Mean free path of electrons
    • Exciton and Bohr exciton radius
    • Other length scales
  • The Density of States function for low dimensional systems
    • The quantum well
    • The quantum wire
    • The quantum dot

• Problems

The following sections are included:

• Introduction

• Energy levels and change in band gap with size in quantum dots

• Coulomb blockade in a quantum dot

• Formation of self assembled quantum dots by epitaxial deposition
  • Introduction
  • Quantum dots by epitaxial deposition
  • Energetics of self assembled quantum dot formation — the Stranski–Kranstanow growth
  • Stacked layers of quantum dot arrays

• Applications of quantum dots

• Problem

The following sections are included:

• Introduction

• Optical properties of bulk metals

• Interaction of light with metal nanoparticles

• Surface plasmon resonance
  • Introduction
  • Effect of particle shape
  • Applications

• Problems

The following sections are included:

• Introduction

• Definitions
  • Magnetic lines of force
  • Magnetic field
  • Magnetic moment and magnetization
  • Magnetic moment of an atom
  • Magnetic moment of a solid

• Classification of magnetic materials
  • Diamagnetic materials
  • Paramagnetic materials
  • Ferromagnetic materials
  • Antiferromagnetic and ferrimagnetic materials

• Nanoscale ferromagnetic materials
  • Magnetization curve of a ferromagnetic crystal
  • Magnetic anisotropy
    • Magnetocrystalline anisotropy
    • Shape anisotropy
    • Surface anisotropy
  • Superparamgnetism
  • Superparamagnetic materials: Ferrofluids
  • Nanostructures exploiting the shape anisotropy
  • Spin dependent scattering: The Giant Magnetoresistance (GMR)

• Problems

The following sections are included:

• Introduction

• The van der Waal's forces
  • Introduction
  • The van der Waal's forces between particles
  • Effect of the particle geometry
    • Plane parallel plates
    • Two equal spheres
    • Sphere and a plate
  • Charge on the particle surfaces
  • Zeta potential and the isoelectric point
  • Electrostatic stabilization: The electrical double layer
    • Introduction
    • Thickness of the double layer
    • Controlling the stability of the electrostatically stabilized suspensions

• Steric stabilization of suspensions
  • Introduction
  • Mechanism
  • Requirement on the chain length

• Colloidal crystals for photonic applications
  • Introduction
  • Soft and hard interactions
  • Preparation of colloidal crystals

• Problems

The following sections are included:

• Introduction

• Structure
  • Structure of graphite
  • Structure of graphene
  • Structure of fullerene
  • Structure of carbon nanotubes

• Preparation of carbon nanotubes
  • The arc–discharge method
  • Laser vaporization
  • Chemical vapor deposition
  • Patterned growth of carbon nanotubes
  • Theories of nanotube growth

• Preparation of graphene

• Properties
  • Mechanical properties
  • Theoretical modeling of the modulus, strength and fracture
  • Experimental measurements of modulus and strength
• Electrical properties
  • Electrical properties of graphene
  • Electrical properties of carbon nanotubes

• Applications of carbon nanotubes
  • Composites
  • Field emission
  • Conductive composites
  • Other applications

• Problems

The following sections are included:

• Introduction

• Growth of one dimensional nanostructures
  • The vapor-liquid-solid (VLS) nanowire growth process
    • Dependence of growth rate on the diameter
    • Conditions for nanowire growth
  • Template assisted growth of nanowires
  • Exploitation of inherent or induced surface energy anisotropy

• Selected properties and applications

• Problems

The following sections are included:

• Introduction

• Thin film deposition
  • Some considerations in thin film deposition
  • Physical vapor deposition (PVD)
  • Chemical vapor deposition
  • The sol – gel process
    • Introduction
    • Sols from metal salts
    • Sols from alkoxides
    • Thin film deposition from a sol
    • Cracking of gels and films
    • Preparation of mesoporous materials
  • Atomic Layer Deposition (ALD)
  • Layer–by–layer (LBL) deposition
    • Introduction
    • The layer–by–layer deposition process
    • Controlling the thickness of the individual layers
    • Incorporating nanoparticles in an LBL film
    • Surface functionalization of nanoparticles

• Multilayers for mechanical engineering applications
  • Introduction
  • The hardening mechanisms for superlattices
    • Dislocation nucleation and multiplication within a layer
    • Dislocation movement across an interface
    • Comparison with experiments
  • Mechanisms for nanocomposite coatings

• Problems

The following sections are included:

• Introduction

• Preparation of bulk nanocrystalline metals
  • Consolidation of fine metal powder by cold compaction
  • Electrodeposition
  • Crystallization of metallic glasses
  • Severe plastic deformation (SPD)
  • Nanocrystalline steel by thermomechanical working

• Mechanical properties of nanoscale metals
  • Hardness and nanoindentation
  • Effect of nano-grain size on the concentration of defects
  • Effect of grain size on the yield strength: the inverse Hall–Petch effect
  • Ductility of the nanocrystalline metals

• Problems

The following sections are included:

• Introduction

• Introduction to the mechanical properties of composites
  • Modulus and strength of the unidirectional fiber reinforced composites
  • Short fiber and particle reinforced composites
    • Importance of the aspect ratio
    • Modulus and strength of short fiber composites
    • The Halpin–Tsai and Mori–Tanaka formulations

• Polymer–CNT nanocomposites
  • Introduction
  • Some important considerations in CNT–composites
    • Aspect ratio of the CNT
    • Shear strength of the matrix–CNT interface
    • Dispersion of the nanotubes in the matrix
    • Waviness of the nanotubes
  • Processing and properties of the polymer–CNT composites

• Polymer–clay nanocomposites
  • Filled polymers vs. the polymer nanocomposites
  • Clays used in the nanocomposites
  • Preparation of the polymer–exfoliated clay nano-composites
  • Properties of the polymer–clay nanocomposites
    • Introduction
    • Mechanical properties
    • The barrier properties of the polymer nanocomposites
    • The nanoeffects

• Problems

The following sections are included:

• Polymers
  • Some common polymers
  • Properties of polymers
    • Molecular weight
    • Length of a polymer chain
    • Bonding within and between polymer chains: thermoplastics, thermosets and elastometers
    • Glass transition temperature
  • Crystalline polymers
  • Polymer solutions: Phase separation

• Polyelectrolytes

• Copolymers
  • Types of copolymers
  • Phase separation in block copolymers

• Biopolymers
  • Proteins
  • Nucleic acids
    • Deoxyribonucleic acid (DNA)
    • Ribonucleic acid (RNA)

• Surfactants
  • Introduction
  • Types of surfactants
  • Absorption of surfactant molecules in a solution
    • Introduction
    • The Gibbs absorption equation

• Dendrimers
  • Synthesis
  • Properties and applications

• Problems

The following sections are included:

• Introduction

• Interactions important in self assembly
  • Ionic and electrostatic interactions
  • The π–interactions
  • The hydrogen bond
  • van der Waals interactions
  • Coordinative bond and coordination complex
  • Dative bond
  • The hydrophobic effect

• Examples of self assembled systems
  • Self assembled monolayers (SAM)
  • Self assembly of amphiphiles into nanostructures
    • The critical micelle concentration (CMC)
    • Spherical micelle — the simplest amphiphile nanostructure
    • Other nanostructures — relation to the packing factor
  • Langmuir–Blodgett (L–B) films
    • Deposition of nanoparticles films using the L–B technique
  • Liquid crystals
  • Dendrimer self assembly

• Problems

The following sections are included:

• A.1. Appendix 1: Description of crystal structure

• A.2. Appendix 2: Review of the mechanical properties of crystalline solids

• References

• Index