Department of Chemistry
Subject: Chemistry Subject Code: 18BSCH03
Module 4
Nanomaterials and their Spectroscopic characterization (12 hours)
Introduction, preparation of nanomaterials: Top down and bottom up approaches, mechanical
grinding, wet chemical synthesis (Sol-gel method). Properties of nanomaterials: optical
properties, electrical properties, magnetic properties, Applications of nanomaterials.
Principles, instrumentation and applications of UV-Vis spectroscopy (UV-VIS), Infra-red
spectroscopy, X-ray diffraction (powder) and scattering (Scanning Electron Microscope)
methods.
1
,Introduction
Nanomaterials are cornerstones of nanoscience and nanotechnology. Nanostructure science
and technology is a broad and interdisciplinary area of research and development activity that
has been growing explosively worldwide in the past few years. Richard P. Feynman (Nobel
Laureate in Physics, 1965) is often credited for introducing the concept of nanotechnology
about 50 years ago. In the annual meeting of the American Physical Society at California
Institute of Technology on 26 December 1959, he delivered a famous lecture entitled
“There’s Plenty of Room at the Bottom”. He also suggested that it would be possible to
arrange the atoms the way we want.
The use of nano-structured materials is not a recently discovered era. It dates back at the
fourth century AD when Romans were using nano-sized metals to decorate glasses and cups.
One of the first known, and most famous example, is the Lycurgus cup.
The term nano originated from the Greek nano’s which means ‘dwarf’. It is one billionth of a
meter. Therefore, whenever we think about nanoscience or nanotechnology, very small
objects come to the mind. Indeed, this branch of science and technology deals with materials
having at least one spatial dimension in the size range of 1 to 100 nm.
2
, Nanomaterials are expected to have a wide range of applications in various fields such as
electronics, optical communications and biological systems. These applications are based on
factors such as their physical properties, huge surface area and small size which offer
possibilities for manipulation and room for accommodating multiple functionalities.
Synthetic approaches for nanomaterials
(i) Top-down approach: The process of making nanostructures starting with larger
structures and breaking away to nano size is called top-down approach.
Ex: Lithography, Ball milling, Epitaxy, etc.
(ii) Bottom-up approach: The building of nanostructures starting with small components
such as atoms or molecules is called bottom-up approach.
Ex: Chemical vapour deposition, Sol-Gel Process, Chemical Reduction methods, etc.
There are many different ways of creating nanostructures: of course, macromolecules or
nanoparticles or bucky-balls or nanotubes and so on can be synthesized artificially for certain
specific materials. They can also be arranged by methods based on equilibrium or near
equilibrium thermodynamics such as methods of self-organization and self-assembly
(sometimes also called bio-mimetic processes). Using these methods, synthesized materials
can be arranged into useful shapes so that finally the material can be applied to a certain
application.
Mechanical grinding (Ball milling)
3
Subject: Chemistry Subject Code: 18BSCH03
Module 4
Nanomaterials and their Spectroscopic characterization (12 hours)
Introduction, preparation of nanomaterials: Top down and bottom up approaches, mechanical
grinding, wet chemical synthesis (Sol-gel method). Properties of nanomaterials: optical
properties, electrical properties, magnetic properties, Applications of nanomaterials.
Principles, instrumentation and applications of UV-Vis spectroscopy (UV-VIS), Infra-red
spectroscopy, X-ray diffraction (powder) and scattering (Scanning Electron Microscope)
methods.
1
,Introduction
Nanomaterials are cornerstones of nanoscience and nanotechnology. Nanostructure science
and technology is a broad and interdisciplinary area of research and development activity that
has been growing explosively worldwide in the past few years. Richard P. Feynman (Nobel
Laureate in Physics, 1965) is often credited for introducing the concept of nanotechnology
about 50 years ago. In the annual meeting of the American Physical Society at California
Institute of Technology on 26 December 1959, he delivered a famous lecture entitled
“There’s Plenty of Room at the Bottom”. He also suggested that it would be possible to
arrange the atoms the way we want.
The use of nano-structured materials is not a recently discovered era. It dates back at the
fourth century AD when Romans were using nano-sized metals to decorate glasses and cups.
One of the first known, and most famous example, is the Lycurgus cup.
The term nano originated from the Greek nano’s which means ‘dwarf’. It is one billionth of a
meter. Therefore, whenever we think about nanoscience or nanotechnology, very small
objects come to the mind. Indeed, this branch of science and technology deals with materials
having at least one spatial dimension in the size range of 1 to 100 nm.
2
, Nanomaterials are expected to have a wide range of applications in various fields such as
electronics, optical communications and biological systems. These applications are based on
factors such as their physical properties, huge surface area and small size which offer
possibilities for manipulation and room for accommodating multiple functionalities.
Synthetic approaches for nanomaterials
(i) Top-down approach: The process of making nanostructures starting with larger
structures and breaking away to nano size is called top-down approach.
Ex: Lithography, Ball milling, Epitaxy, etc.
(ii) Bottom-up approach: The building of nanostructures starting with small components
such as atoms or molecules is called bottom-up approach.
Ex: Chemical vapour deposition, Sol-Gel Process, Chemical Reduction methods, etc.
There are many different ways of creating nanostructures: of course, macromolecules or
nanoparticles or bucky-balls or nanotubes and so on can be synthesized artificially for certain
specific materials. They can also be arranged by methods based on equilibrium or near
equilibrium thermodynamics such as methods of self-organization and self-assembly
(sometimes also called bio-mimetic processes). Using these methods, synthesized materials
can be arranged into useful shapes so that finally the material can be applied to a certain
application.
Mechanical grinding (Ball milling)
3
