Summary Electrical Engineering Chemistry for Beginners
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Chemistry
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IFET COLLEGE OF ENGINEERING
(An Autonomous Institution)
DEPARTMENT OF ECE&EEE
UNIT-V- NANOTECHNOLOY
MODULE
SUBJECT CODE: 23CH2202 Year / Sem: I/II
SUBJECT NAME: CHEMISTRY FOR ELECTRONCIS ENGINEERS
5.I NTRODUCTION
Nanochemistry is the branch of nanoscience, which deals with the chemical applications of
nanomaterials. It also includes the study of synthesis and characterization of nanomaterials.
The applications of nanochemistry have a wide range which covers from the semiconductors
electronics to medicine. Nanochemistry uses semi-conductors that only conduct electricity in
specific conditions
5.2 BASICS OF NANO CHEMISTRY
1. Nanoparticles: A nanoparticle (or nanopowder or nanocluster or nanocrystal) is a
microscopic particle with at least one dimension less than 100 nm. They can possess physical
properties such as uniformity, conductance or special optical properties that make them
desirable in materials science and biology.
2. Nanomaterials: Nano materials are the materials having components with size less than
100 nm at least in one dimension. Nano materials have a much greater surface area to volume
ratio than their conventional forms, which can lead to greater chemical reactivity.
3. Nanoscience: Nanoscience is the study of phenomena and manipulation of materials
between molecular and nanometer size. Nano science is the study of structures and materials
on the scale of nanometers.
4. Nano-technology: Nano-technology is the design, fabrication, characterization and
applications of materials at nano-level (1-100 nm) and converting them into useful devices.
Nanotechnology is the engineering of functional systems at the molecular scale.
5.3. DISTINCTION BETWEEN NANO PARTICLES, MOLECULES AND BULK
MATERIALS
1. The size of nano particles are less than 100 nm in diameter, molecules are in the
range of picometers,but bulk materials are larger in micron size.
2. Molecule is a collection of atoms, nano particles are collection of few molecules that
is less than 100nm but bulk materials contains thousands of molecules.
3. Surface area of nano particles is more than the bulk materials.
4. Hardness of nano materials is 5 times more than the bulk materials.
5. Strength of nano materials is 3 - 10 times higher than the bulk materials.
6. Nano particles possesses size dependent properties, but bulk materials possess
constant physicalproperties.
, 7. Corrosion resistance is more than the bulk materials, hence localised corrosion in
nano materials isstopped.
8. Behavior of bulk materials can be changed, but cannot enter inside the nano particles.
9. Nano particles, due to its size, possess unexpected optical (visible) properties.
Ex: Gold nano particles appear deep red to black colour in solution compared to
yellow colour withGold.
10. Nanoparticles possesses lower melting point than the bulk materials
Ex: Gold nanoparticles melt at lower temperature (300°C) for 2.5 nm, but Gold slab melts
at 1064°C.
S.NO PROPERTIES ATOM/ NANOPARTICLES/ BULK
MOLECULES CLUSTERS MATERIALS
1 Size of constituting Few Angstrom to Microns to
particles Angstroms(Å) nanometer (10-10 m higher
(10-10 m) to 10-9 m)
2 Number of constituting 1 for atom, 2 to several Infinite
particles. many for thousands.
molecules.
3 Electronic structure Confined. Confined. Continuous
4 Geometric structure Well-defined Well-defined Crystal structure
structure and structure and decides.
predictable. predictable.
5 Example NaCl, HCl (NaCl)n Gold bar &
Silver bar
5.4 NANOPARTICLES: Nanoparticles are the particles, the size of which range from 1 to 100 nm.
They are tiny aggregates of atoms but smaller than their crystal but bigger than molecule. They
have three dimensional structures.
Examples: 1. TiO2 (Titanium oxide) ,
1. Gold.
2. Silver.
3. ZnO.(Zinc Oxide)
Properties of Nanoparticles:
Quantum confinement in semiconductor particles.
Nano particle have a very high surface area to volume ratio.
Sintering take place at low temperature.
Nano particles often have unexpected visible properties because they are small enough to
confine their electrons and produce Quantum effect. There is significant shift in the
optical absorption spectra towards blue (shorter wavelength) as the particle size reduced.
Surface plasmon resonance in certain metallic nano particles.
Applications of nanoparticles
TiO2 is used in cosmetic as they are very good UV- absorber.
Nano silver particles are used as a catalyst in industries.
, Nanoparticles are used in medicine.
The use of polymeric micelle nanoparticles to deliver drugs to tumors.
Nano silver particles are used in making bone cement, surgical instruments, etc.,
5.5 NANO-RODS: Nanorod is two dimensional cylindrical solid material having an aspect
ratio i.e., length to width ratio less than 20. Examples: Zinc oxide, cadmium sulphide.
Nanorods are also referred to as “quantum rods”.
Fig 5. 1 Nano Rod
5.5.1 Synthesis of nanorods
Nano-rods are produced by direct chemical synthesis. A combination of ligands acts as shape
control agents and bond to different facets of the nano-rods with different strength. This
allows different nanorods to grow at different rates producing elongated objects.
Fig 5.2 Nanorod
5.5.2 Properties of nanorods
Nano – rods are one dimensional materials
It also exhibits optical and electrical properties
5.5.3 Applications of nanorods:
Nanorods find application in display technologies. It is also used in the manufacturing
of micro mechanical switches. Nanorods are used in an applied electric field, micro
electro mechanical systems,
Nanorods along with noble metal nanoparticles function as theragnostic agents.
They are used in energy harvesting and light emitting devices. Nanorods have used as
cancer therapeutics.
5.6 NANOCLUSTER: Nanoclusters are fine aggregates of atoms or molecules. The size of
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