PHYSICS FUNDAMENTAL AND DEVICE Week 1.pdf
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About This Presentation
PHYSICS FUNDAMENTAL AND DEVICE
Slide Content
Physics of Functional Materials & Devices
Prof. Amreesh Chandra
Department of Physics, IIT KHARAGPUR
Module01: Introduction to Functional Materials
Lecture 01 : Introduction to solid state materials –From conventional to functionalNPTEL
Prof. Amreesh Chandra
Department of Physics, IIT KHARAGPUR
Module01: Introduction to Functional Materials
Lecture 01 : Introduction to solid state materials –From conventional to functionalNPTEL
❑Introduction
❑Classification of Materials
❑Functional Solid State Materials
❑Different Types of Functional
M
aterials
❑Applications of Functional
M
aterialsNPTEL
❑Classification of Materials
❑Functional Solid State Materials
❑Different Types of Functional
M
aterials
❑Applications of Functional
M
aterialsNPTEL
Introduction
Physics:Itisasubjectthatdealswiththescienceofmatter, motionandenergy(bothutilizationandtransport).
If you look around, there is growing need that a given device should have the capability to be used for more than one
applications. Take the example of a smart mobile phone –it can be used for communication, camera, audio player,
audio recorder, torch, projector, scanner, etc.
Materials: Made up of matter.
Question that can be asked:
????????????How are they made? and What drives their formation?
M
ost of the answers lie in the postulates of physics. Therefore, the term of physics of materials is routinely used and
understood. This should have been the topic of the course. But it is slightly different?
Why?
The genesis of the answer lies in the question, which is mostly asked today: what is the application of these materials? This is a
common question, which is being asked to people working with materials.
Functional Materials are a class of materials, which have a various types of functions/
applications but with atleast 2 or > 2 functionalities.
Example of multiferroic ceramics: Same material can be used for electric as well as magnetic
sensors as well as a dielectric in a capacitor.
Therefore, the topic that is relevant in today’s world is: “Physics of functional materials”. This
will covered in this 12-week course.
Before, giving the reason for the choice of the course title, let me explain the meaning of the term: FUNCTIONALNPTEL
Physics:Itisasubjectthatdealswiththescienceofmatter, motionandenergy(bothutilizationandtransport).
If you look around, there is growing need that a given device should have the capability to be used for more than one
applications. Take the example of a smart mobile phone –it can be used for communication, camera, audio player,
audio recorder, torch, projector, scanner, etc.
Materials: Made up of matter.
Question that can be asked:
????????????How are they made? and What drives their formation?
M
ost of the answers lie in the postulates of physics. Therefore, the term of physics of materials is routinely used and
understood. This should have been the topic of the course. But it is slightly different?
Why?
The genesis of the answer lies in the question, which is mostly asked today: what is the application of these materials? This is a
common question, which is being asked to people working with materials.
Functional Materials are a class of materials, which have a various types of functions/
applications but with atleast 2 or > 2 functionalities.
Example of multiferroic ceramics: Same material can be used for electric as well as magnetic
sensors as well as a dielectric in a capacitor.
Therefore, the topic that is relevant in today’s world is: “Physics of functional materials”. This
will covered in this 12-week course.
Before, giving the reason for the choice of the course title, let me explain the meaning of the term: FUNCTIONALNPTEL
Solid state materials
✔A solid is a state of matter that preserves its shape and volume when not
c
onfined.
✔Solids state materials are characterized by features like inc
ompressibility, rigidityand high mechanical
strength.
Properties & definition of
solids:
Three state of matter: Solid, Liquid,
Gas
Solid
✔Definite shape
✔Definite volume
✔Definite mass
✔High density
Liquid
×Definite shape
✔Definite volume
✔Definite mass
✔Medium density
Gas
×Definite shape
×Definite volume
✔Definite mass
✔Low density
✔The atoms or molecules in solids are closely packed and they are held together
b
y strong forces and can not move at random.
✔In solids there are some ordered/random arrangement of molecules, atom or
i
ons.NPTEL
✔A solid is a state of matter that preserves its shape and volume when not
c
onfined.
✔Solids state materials are characterized by features like inc
ompressibility, rigidityand high mechanical
strength.
Properties & definition of
solids:
Three state of matter: Solid, Liquid,
Gas
Solid
✔Definite shape
✔Definite volume
✔Definite mass
✔High density
Liquid
×Definite shape
✔Definite volume
✔Definite mass
✔Medium density
Gas
×Definite shape
×Definite volume
✔Definite mass
✔Low density
✔The atoms or molecules in solids are closely packed and they are held together
b
y strong forces and can not move at random.
✔In solids there are some ordered/random arrangement of molecules, atom or
i
ons.NPTEL
Classifications on the basis of atomic arrangements
Dependingonthe arrangementof atomsormolecules,solidstatematerials canbedivided into
threecategories:
Single crystalline
solids
Polycrystalline solids Amorphous solids
•Diamon
d
•Ice
•Quartz
•Common
M
etals
•Ceramics
•Plastics
•Rubbers
•Polymer
s
Theperiodicityof atomsextends
throughoutthematerial.
A numberofsmallcrystallites
withrandom orientations
separated by well-defined
boundaries. This small
crystallitesareknownasgrains.
Withinthecrystallites, there is
long range ordering. Theyhaverandomarrangement,with
shortrangeordering.
Examples
:
Examples
:
Examples
:NPTEL
Dependingonthe arrangementof atomsormolecules,solidstatematerials canbedivided into
threecategories:
Single crystalline
solids
Polycrystalline solids Amorphous solids
•Diamon
d
•Ice
•Quartz
•Common
M
etals
•Ceramics
•Plastics
•Rubbers
•Polymer
s
Theperiodicityof atomsextends
throughoutthematerial.
A numberofsmallcrystallites
withrandom orientations
separated by well-defined
boundaries. This small
crystallitesareknownasgrains.
Withinthecrystallites, there is
long range ordering. Theyhaverandomarrangement,with
shortrangeordering.
Examples
:
Examples
:
Examples
:NPTEL
Classifications on the basis of energy band gap
MetalsSemiconductors Insulators
Solid state
materials
Energy band gap Example
Metal No band gap Copper, zinc, iron
Insulator > 3eV Glass, wood, plastic
Semiconductor < 3eV Silicon, germanium
Band
gap:
Thebandgapis definedas theenergy,inelectronvolts,
neededfor anelectrontojumpfromthevalencebandto
the conduction band.
What is the origin of band gap in solids?NPTEL
MetalsSemiconductors Insulators
Solid state
materials
Energy band gap Example
Metal No band gap Copper, zinc, iron
Insulator > 3eV Glass, wood, plastic
Semiconductor < 3eV Silicon, germanium
Band
gap:
Thebandgapis definedas theenergy,inelectronvolts,
neededfor anelectrontojumpfromthevalencebandto
the conduction band.
What is the origin of band gap in solids?NPTEL
Various other conventional materials
Transition metal oxides: Manganese oxides (MnO
2/Mn
3O
4), Cobalt oxides (Co
3O
4), Copper oxides
(Cu
2O/CuO), etc.
Transition metal Sulfides: Molybdenum disulfide (MoS
2), Tin disufide (SnS
2), Tungsten disulfide
(WS
2), etc.
Conducting polymer:Polyaniline (PANI), Polypyrrole (PPy),
etc.
Carbons:Activated carbon (AC), Graphite
powder
Metal organic framework: ZIF-67 (C
8H
10N
4Co), ZIF-8 (C
8H
10N
4Zn), HKUST-1
(C
18H
6Cu
3O
12), etc.
Metal organic framework
⮚Can b
functionalized
byexfoliatingthe2D
layers
⮚Lowe
⮚Can b
functionalizedby
makingcomposite with
highly conductivepolymer
or carbontoincreasethe
conductivity
Transition metal
sulfidesNPTEL
Transition metal oxides: Manganese oxides (MnO
2/Mn
3O
4), Cobalt oxides (Co
3O
4), Copper oxides
(Cu
2O/CuO), etc.
Transition metal Sulfides: Molybdenum disulfide (MoS
2), Tin disufide (SnS
2), Tungsten disulfide
(WS
2), etc.
Conducting polymer:Polyaniline (PANI), Polypyrrole (PPy),
etc.
Carbons:Activated carbon (AC), Graphite
powder
Metal organic framework: ZIF-67 (C
8H
10N
4Co), ZIF-8 (C
8H
10N
4Zn), HKUST-1
(C
18H
6Cu
3O
12), etc.
Metal organic framework
⮚Can b
functionalized
byexfoliatingthe2D
layers
⮚Lowe
⮚Can b
functionalizedby
makingcomposite with
highly conductivepolymer
or carbontoincreasethe
conductivity
Transition metal
sulfidesNPTEL
Functionalized solid state materials
Till now, the discussed materials are conventional solid state
materials
Functional solid state materials
Functionalization is the process of adding new functions, features,
capabilities, or properties to a material by changing the surface chemistry
of the material. NPTEL
Till now, the discussed materials are conventional solid state
materials
Functional solid state materials
Functionalization is the process of adding new functions, features,
capabilities, or properties to a material by changing the surface chemistry
of the material. NPTEL
Functionalization is the process of adding new functions, features,
capabilities, or properties to a material by changing the surface chemistry
of the material. NPTEL
capabilities, or properties to a material by changing the surface chemistry
of the material. NPTEL
Different types of functionalization
Functionalization in size/
dimension
Functionalization of shape/
morphology
Functionalization of pore
architecture
Functionalization of
conductivity
From bulk to nanomaterials
[From 3D to 2D to 1D to 0D
nanomaterials]
Solid sphere, Hollow sphere, Rod, Cactus, Urchin like
Increment of
conductivitybydoping
ormakingcomposite
withcarbon or polymer
Tuning porous networkNPTEL
Functionalization in size/
dimension
Functionalization of shape/
morphology
Functionalization of pore
architecture
Functionalization of
conductivity
From bulk to nanomaterials
[From 3D to 2D to 1D to 0D
nanomaterials]
Solid sphere, Hollow sphere, Rod, Cactus, Urchin like
Increment of
conductivitybydoping
ormakingcomposite
withcarbon or polymer
Tuning porous networkNPTEL
Functionalization in size
Bul
k
Nanomateria
l
Nano -a billionth –(1 x 10
-9
)
Nanomaterials: Special class of materials, which have at least one of the dimensions in
the range 1- 100 nm.
✔In1960 ,he deliveredalecture,inameeting ofAPS,withtitle:“ThereisPlentyof Roomatthe
Bottom”,wherehe indicated that the ‘novel’ physics can evolveifnanosized materials were
investigated carefully.
✔Richard F
isconsidered as the ‘Father’ of modern day nanotechnologyNPTEL
Bul
k
Nanomateria
l
Nano -a billionth –(1 x 10
-9
)
Nanomaterials: Special class of materials, which have at least one of the dimensions in
the range 1- 100 nm.
✔In1960 ,he deliveredalecture,inameeting ofAPS,withtitle:“ThereisPlentyof Roomatthe
Bottom”,wherehe indicated that the ‘novel’ physics can evolveifnanosized materials were
investigated carefully.
✔Richard F
isconsidered as the ‘Father’ of modern day nanotechnologyNPTEL
Size effects
Parameters Changes
Melting point Decreases
Surface Area Increases
Electrical Increases
Mechanical Increase strength
Optical Change in colour
Magnetic SuperparamagneticNPTEL
Parameters Changes
Melting point Decreases
Surface Area Increases
Electrical Increases
Mechanical Increase strength
Optical Change in colour
Magnetic SuperparamagneticNPTEL
Functionalization in dimensionality
✔Thematerial canbe0-di mentional(0D),1-dimentional(1D),2-dimentional(2D), and3-dimentional(3D).
0D nanomaterials
•Quantum dots
(Q
Ds)
•Nanospheres
•Nano-lenses
•Nan
o-onions
1D nanomaterials
•Nanorods
•Nanowires
•Nanobelts
•Nanotubes
2D nanomaterials
•Nanoplates
•Nanosheets
•Nanowalls
•Nanodisks
3D materials
•Bulk material
✔0Dnanomaterialsh
aveapplicationsinlight emittingdiodes(LEDs),lasers,andsolar
cell applications.
✔1D nanomaterialsh
aveapplications in electronicand optoelectronicdevices.
Few example of applications:NPTEL
✔Thematerial canbe0-di mentional(0D),1-dimentional(1D),2-dimentional(2D), and3-dimentional(3D).
0D nanomaterials
•Quantum dots
(Q
Ds)
•Nanospheres
•Nano-lenses
•Nan
o-onions
1D nanomaterials
•Nanorods
•Nanowires
•Nanobelts
•Nanotubes
2D nanomaterials
•Nanoplates
•Nanosheets
•Nanowalls
•Nanodisks
3D materials
•Bulk material
✔0Dnanomaterialsh
aveapplicationsinlight emittingdiodes(LEDs),lasers,andsolar
cell applications.
✔1D nanomaterialsh
aveapplications in electronicand optoelectronicdevices.
Few example of applications:NPTEL
Functionalization in dimensionality of carbon
Fullerene
s
1985
Carbon
nanotubes
1991
Graphen
e
2004
Graphit
e
1890
0D 1
D
2D 3D
Applications of
graphene:
✔Grapheneh aswideapplicationinenergy industry,medicine,
electronics,food industry,etc.
Applications of fullerenes:
✔0Dn haveshown
greatpotentialiniondetection,
biomolecular recognition, diseasediagnosisandpathogen
detection.
Applications of carbon nanotubes:
✔Carbonn areutilized in
energy storage, device
modelling,automotiveparts,
water filters, thin-film
electronics, actuators,
electromagnetic shields, etc.
Applications of graphite:
✔Graphite isu sedinrefractoryindustry,commercializedLi-ion
battery, and asalubricants.Also,themostwellknownmarketof
graphiteisitsuseinpencil.
Nobel prize in Physics, 2010NPTEL
Fullerene
s
1985
Carbon
nanotubes
1991
Graphen
e
2004
Graphit
e
1890
0D 1
D
2D 3D
Applications of
graphene:
✔Grapheneh aswideapplicationinenergy industry,medicine,
electronics,food industry,etc.
Applications of fullerenes:
✔0Dn haveshown
greatpotentialiniondetection,
biomolecular recognition, diseasediagnosisandpathogen
detection.
Applications of carbon nanotubes:
✔Carbonn areutilized in
energy storage, device
modelling,automotiveparts,
water filters, thin-film
electronics, actuators,
electromagnetic shields, etc.
Applications of graphite:
✔Graphite isu sedinrefractoryindustry,commercializedLi-ion
battery, and asalubricants.Also,themostwellknownmarketof
graphiteisitsuseinpencil.
Nobel prize in Physics, 2010NPTEL
Functionalization in morphology
By changing the morphology of the materials we can tune the various physical and chemical
properties of the materials.
❑Thesu tovolumeratioishigh for hollow
structured materialincomparetotheir solid
counterparts.
❑Hollowst
highlybeneficialfor
energy storage devices, catalyticapplicationsandfor
sensingapplications.
❑Capped an
bowl like carbonoffershigheractive
siteswithgreater electricalconductivitythanthe
conventionalactivated carbon.
NaFePO
4 Capped carbon
Bowl like carbon
Hollow
Scanning electron microscopic (SEM) images of the various
synthesized materials
Createdchannelfor
transportation of ions
Higheractivesites
Na
2Ti
3O
7
Commercialized
activated carbonNPTEL
By changing the morphology of the materials we can tune the various physical and chemical
properties of the materials.
❑Thesu tovolumeratioishigh for hollow
structured materialincomparetotheir solid
counterparts.
❑Hollowst
highlybeneficialfor
energy storage devices, catalyticapplicationsandfor
sensingapplications.
❑Capped an
bowl like carbonoffershigheractive
siteswithgreater electricalconductivitythanthe
conventionalactivated carbon.
NaFePO
4 Capped carbon
Bowl like carbon
Hollow
Scanning electron microscopic (SEM) images of the various
synthesized materials
Createdchannelfor
transportation of ions
Higheractivesites
Na
2Ti
3O
7
Commercialized
activated carbonNPTEL
Functionalization of conductivity
Transition metal oxides, and metal organic frameworks generally suffers from low electrical
conductivity.
✔Wecan i
theconductivity ofthese materialsbymakingcompositewithhighlyconductive
carbonorpolymer.
✔Wecan i
theconductivity ofthese materialsby doping orcreating vacancyinthematerials.
MOF
Polypyrrole
Example
:
MOF @ Polypyrrole compositeNPTEL
Transition metal oxides, and metal organic frameworks generally suffers from low electrical
conductivity.
✔Wecan i
theconductivity ofthese materialsbymakingcompositewithhighlyconductive
carbonorpolymer.
✔Wecan i
theconductivity ofthese materialsby doping orcreating vacancyinthematerials.
MOF
Polypyrrole
Example
:
MOF @ Polypyrrole compositeNPTEL
How we can introduce functionality in the
material?
✔Anefficientway ofincorporating
functionality in various conventional
materials is directlyduringtheir synthesis.
✔Byfollowingdifferentsynthesisprotocols
we can tune the chemical, electrical,
opticalandthermal propertiesofthe
material.
Each synthesisprocedurewillbediscussed
intheupcomingclasses.NPTEL
material?
✔Anefficientway ofincorporating
functionality in various conventional
materials is directlyduringtheir synthesis.
✔Byfollowingdifferentsynthesisprotocols
we can tune the chemical, electrical,
opticalandthermal propertiesofthe
material.
Each synthesisprocedurewillbediscussed
intheupcomingclasses.NPTEL
Applications of functional materials
❖Electromagnetic materials:Semiconductordevices,organicelectronics,flexibledevices.
Example:Silicon, germanium, polymer,etc.
❖Photonicsm
aterials:Lasers,LEDs,fiberoptics,waveguides.
Example:Galliumarsenide(GaAs), Aluminium galliumarsenide (AlGaAs)
❖Catalytic m
aterials:Carexhausts,molecularsynthesis.
Example:Paladium, Platinum, Transitionmetal oxides(TMOs)NPTEL
❖Electromagnetic materials:Semiconductordevices,organicelectronics,flexibledevices.
Example:Silicon, germanium, polymer,etc.
❖Photonicsm
aterials:Lasers,LEDs,fiberoptics,waveguides.
Example:Galliumarsenide(GaAs), Aluminium galliumarsenide (AlGaAs)
❖Catalytic m
aterials:Carexhausts,molecularsynthesis.
Example:Paladium, Platinum, Transitionmetal oxides(TMOs)NPTEL
Applications of functional materials
❖Energym Batteries,hydrogenstorage.
Example:Transitionmetal oxides, Graphene,Transitionmealsulfides,MOF
❖SUPERm
Superconductors,supercapacitors,giantmagnetoresistancematerials.
Example:Aluminium,Niobium,Magnesiumdiboride,Carbon,Metal oxides
❖Magical m
aterials:Metamaterials,negativetransportproperties,negativerefractive
index.
Example:Iron,Nickel,CobaltNPTEL
❖Energym Batteries,hydrogenstorage.
Example:Transitionmetal oxides, Graphene,Transitionmealsulfides,MOF
❖SUPERm
Superconductors,supercapacitors,giantmagnetoresistancematerials.
Example:Aluminium,Niobium,Magnesiumdiboride,Carbon,Metal oxides
❖Magical m
aterials:Metamaterials,negativetransportproperties,negativerefractive
index.
Example:Iron,Nickel,CobaltNPTEL
❑As state materialhasdefiniteshape and volume,evenwhenit isnot confined.
❑Depending on t
hearrangementofatomsormolecules,solidstatematerials canbedivided
intothreecategories: Singlecrystalline,Polycrystalline,and Amorphous.
❑Ont
basisofenergyband gap,solidstatematerials canbedivided intothree categories:
Metal,Insulator, and Semiconductor.
❑Inc
toconventionalmaterial,functionalmaterialsposses improvedphysical,
thermal,electrical,andelectrochemicalproperties.
❑The f
materials canbesynthesizedusing a large number ofsynthesisprotocols.NPTEL
❑Depending on t
hearrangementofatomsormolecules,solidstatematerials canbedivided
intothreecategories: Singlecrystalline,Polycrystalline,and Amorphous.
❑Ont
basisofenergyband gap,solidstatematerials canbedivided intothree categories:
Metal,Insulator, and Semiconductor.
❑Inc
toconventionalmaterial,functionalmaterialsposses improvedphysical,
thermal,electrical,andelectrochemicalproperties.
❑The f
materials canbesynthesizedusing a large number ofsynthesisprotocols.NPTEL
⮚Physics of Functional Materials by Hasse Fredriksson & Ulla Akerlind
⮚Introduction to Solid State Physics by Charles Kittle
⮚Introduction to Nanotechnology, Charles P. Poole, Jr. and Frank J.
Owens, wiley-interscience.
⮚A Textbook of Nanoscience and Nanotechnology, P. I. Varghese and
Thalappil, McGraw Hill Education, 2017.NPTEL
⮚Introduction to Solid State Physics by Charles Kittle
⮚Introduction to Nanotechnology, Charles P. Poole, Jr. and Frank J.
Owens, wiley-interscience.
⮚A Textbook of Nanoscience and Nanotechnology, P. I. Varghese and
Thalappil, McGraw Hill Education, 2017.NPTEL
Thank you…NPTEL
Physics of Functional Materials & Devices
Prof. Amreesh Chandra
Department of Physics, IIT KHARAGPUR
Module 01: Introduction to Functional Materials
Lecture 02 : Ceramics and CompositesNPTEL
Prof. Amreesh Chandra
Department of Physics, IIT KHARAGPUR
Module 01: Introduction to Functional Materials
Lecture 02 : Ceramics and CompositesNPTEL
❑Definitiona ndclassificationofceramics.
❑Differentpr
opertiesofceramics.
❑Applicationsofc
eramics.
❑Definitiona
ndclassificationofcomposites.
❑Applicationsofc
ompositesNPTEL
❑Differentpr
opertiesofceramics.
❑Applicationsofc
eramics.
❑Definitiona
ndclassificationofcomposites.
❑Applicationsofc
ompositesNPTEL
Definitions:Aceramicisaninorganicmaterial,whichispreparedathightemperatures.
Ceramicscanbecrystalline,glassy,orbothcrystallineandglassy.
Examples:clay,bricks,glass,tiles,cement,dielectric,oxides,cladding,shields,etc.
CeramicsNPTEL
Ceramicscanbecrystalline,glassy,orbothcrystallineandglassy.
Examples:clay,bricks,glass,tiles,cement,dielectric,oxides,cladding,shields,etc.
CeramicsNPTEL
Importantpointsregardingtheceramicmaterials:
✔Ceramicsarebrittle,hard, oftenverystrong,andresist corrosion.
✔Traditionalceramicsareclay-basedandrelyon clay fortheircreation.
✔Modern-dayceramicsareusing newmaterialsthataren’t clay.
✔Modern-dayceramicsarebased on oxides ornon-oxides or combinations ofthetwo.
✔Theyare refractorytypematerials,whichcanwithstandhightemperatures.
Different ceramic materials
If we look around, we can realize our life revolves around ceramics . From the ceramic-
based electronic components in our computers to the high-end TVs we watch, ceramics are
everywhere.
Ceramics
Can you make a list of ceramics, which are not mentioned till now but are routinely
seen around us?NPTEL
✔Ceramicsarebrittle,hard, oftenverystrong,andresist corrosion.
✔Traditionalceramicsareclay-basedandrelyon clay fortheircreation.
✔Modern-dayceramicsareusing newmaterialsthataren’t clay.
✔Modern-dayceramicsarebased on oxides ornon-oxides or combinations ofthetwo.
✔Theyare refractorytypematerials,whichcanwithstandhightemperatures.
Different ceramic materials
If we look around, we can realize our life revolves around ceramics . From the ceramic-
based electronic components in our computers to the high-end TVs we watch, ceramics are
everywhere.
Ceramics
Can you make a list of ceramics, which are not mentioned till now but are routinely
seen around us?NPTEL
Ceramicsexhibitdifferenttypesofcrystalstructures,whichhavesignificanton
theirproperties. Somearediscussedinnextslides.
Cs
+
Cl
-NPTEL
theirproperties. Somearediscussedinnextslides.
Cs
+
Cl
-NPTEL
Crystalstructuresofceramics
Important points about the crystal structures
✔Crystaloftheceramicsconsistof atoms located at alattice site.
✔Crystalsshouldbe chargeneutral.The numberofpositiveandnegativeionswillbesame.
Somecommoncrystal structuresobservedin ceramic materialsare:
(a) A-X type orrock-salt structure
(b)Zincblendeandwurtzitestructure
(c)Perovskitestructure
(d)Spinelstructure
Take an example of a famous ABO
3type material i.e. BaTiO
3NPTEL
Important points about the crystal structures
✔Crystaloftheceramicsconsistof atoms located at alattice site.
✔Crystalsshouldbe chargeneutral.The numberofpositiveandnegativeionswillbesame.
Somecommoncrystal structuresobservedin ceramic materialsare:
(a) A-X type orrock-salt structure
(b)Zincblendeandwurtzitestructure
(c)Perovskitestructure
(d)Spinelstructure
Take an example of a famous ABO
3type material i.e. BaTiO
3NPTEL
Crystalstructuresofceramics
Electrically neutral It contains an equal number of cations and anions
Cation:Itisatypeof ionthat hasadeficiencyofnegativelychargedelectrons. Cationsareformedwhen theatom
losesoneormoreelectrons.Thisresultsinan overallpositivecharge.
Anion:Itisatypeof ionthat hasanexcessamountofnegativelychargedelectrons.These typesofionsareformedwhen
theatom gainsoneormoreelectrons.Thisresultsinan overall negative charge.
Examples:Ca
2+
,Na
+
,Ti
4+
, Fe
2+
, Fe
3+
,etc.NPTEL
Electrically neutral It contains an equal number of cations and anions
Cation:Itisatypeof ionthat hasadeficiencyofnegativelychargedelectrons. Cationsareformedwhen theatom
losesoneormoreelectrons.Thisresultsinan overallpositivecharge.
Anion:Itisatypeof ionthat hasanexcessamountofnegativelychargedelectrons.These typesofionsareformedwhen
theatom gainsoneormoreelectrons.Thisresultsinan overall negative charge.
Examples:Ca
2+
,Na
+
,Ti
4+
, Fe
2+
, Fe
3+
,etc.NPTEL
Perovskitestructure
Perovskite structure (ABX
3)
✔BaTiO
3isthemostimportantandwidelystudiedperovskite.
✔Int
polarized phase,ithascubicsymmetry. Ba
2+
occupythecornersof acube,the
O
2-
arelocated atthecentersofthefaces,and theTi
4+
isatthecenter.
XA B
✔Aisa di or m onovalentmetal.
✔Bisate
or pentavalentmetal.
✔Veryc
example of
perovskiteisBaTiO
3.
✔A = Ba
2+
, B =Ti
4+
, for BaTiO
3.NPTEL
Perovskite structure (ABX
3)
✔BaTiO
3isthemostimportantandwidelystudiedperovskite.
✔Int
polarized phase,ithascubicsymmetry. Ba
2+
occupythecornersof acube,the
O
2-
arelocated atthecentersofthefaces,and theTi
4+
isatthecenter.
XA B
✔Aisa di or m onovalentmetal.
✔Bisate
or pentavalentmetal.
✔Veryc
example of
perovskiteisBaTiO
3.
✔A = Ba
2+
, B =Ti
4+
, for BaTiO
3.NPTEL
Spinelstructure
Spinel structure
Spinel structured ceramics (AB
2O
4)
✔Examples ofs pinelstructure: MgAl
2O
4,
Mn
3O
4,ZnFe
2O
4, FeCr
2O
4,etc.
✔Examples ofi
nversespinelstructure:
NiAl
2O
4,Mn
3O
4,NiFe
2O
4, CoFe
2O
4,etc.
✔The s
structureshave thegeneral chemicalformula: AB
2X
4,whereA
= a divalent cation (Mg,Cr, MnFe,Ni,etc.), B = atrivalentcation (Al,
Ga,In,Ti,V,Cr,Fe,etc.), X =O,S, Se,etc.
✔As
cellismadeupof 8 FCCcells.
✔The a
oxideions: O
2-
) occupytheFCClattice points.The
divalentA(II)cations occupy 1/8th ofthetetrahedralvoids,whereasthe
trivalentB(III)cations occupyone-half(1/2) of octahedral voids.
✔Also,t
inversespinelstructuredmaterialshave thesamechemical
formulae: AB
2X
4.
✔Unliket
normalspinelstructure,the
inversespinelstructurehasalltheA cations
and halfoftheB cationsoccupying
octahedralsiteswhiletheotherhalfof B
cations occupy tetrahedralsites.NPTEL
Spinel structure
Spinel structured ceramics (AB
2O
4)
✔Examples ofs pinelstructure: MgAl
2O
4,
Mn
3O
4,ZnFe
2O
4, FeCr
2O
4,etc.
✔Examples ofi
nversespinelstructure:
NiAl
2O
4,Mn
3O
4,NiFe
2O
4, CoFe
2O
4,etc.
✔The s
structureshave thegeneral chemicalformula: AB
2X
4,whereA
= a divalent cation (Mg,Cr, MnFe,Ni,etc.), B = atrivalentcation (Al,
Ga,In,Ti,V,Cr,Fe,etc.), X =O,S, Se,etc.
✔As
cellismadeupof 8 FCCcells.
✔The a
oxideions: O
2-
) occupytheFCClattice points.The
divalentA(II)cations occupy 1/8th ofthetetrahedralvoids,whereasthe
trivalentB(III)cations occupyone-half(1/2) of octahedral voids.
✔Also,t
inversespinelstructuredmaterialshave thesamechemical
formulae: AB
2X
4.
✔Unliket
normalspinelstructure,the
inversespinelstructurehasalltheA cations
and halfoftheB cationsoccupying
octahedralsiteswhiletheotherhalfof B
cations occupy tetrahedralsites.NPTEL
Rocksaltstructure
A-X type of crystal structure or rock-salt structure
CationAnion
✔Thec
numberof NaClcrystalis6.
✔Na
+
occupiesoctahedralsitesandCl
-
occupiesatcornersandfacecentersites.
✔It c
of twointerpenetratingFCClattices.
Examples of A-X typecrystal
✔Sodiumc
type)
✔Cesiumc
type)
✔Na
+
occupiesoctahedralsitesandCl
-
occupies
atcornersandfacecentresites.
✔Radiusr
between0.434 – 0.712
✔Radiusr
defined as r
cation/r
anion.
✔Itc
equalnumberof
cationsand anions.
Crystal structure of NaClNPTEL
A-X type of crystal structure or rock-salt structure
CationAnion
✔Thec
numberof NaClcrystalis6.
✔Na
+
occupiesoctahedralsitesandCl
-
occupiesatcornersandfacecentersites.
✔It c
of twointerpenetratingFCClattices.
Examples of A-X typecrystal
✔Sodiumc
type)
✔Cesiumc
type)
✔Na
+
occupiesoctahedralsitesandCl
-
occupies
atcornersandfacecentresites.
✔Radiusr
between0.434 – 0.712
✔Radiusr
defined as r
cation/r
anion.
✔Itc
equalnumberof
cationsand anions.
Crystal structure of NaClNPTEL
RocksaltstructureandZincblende
Crystal structure of CsCl
Another A-X type of crystal structure (CsCl)
✔Radiusratiois0.934.It
approaches 1.
✔Co-ordinationnumberis8.
✔Higherradiusratiomeans
thecationsarelarge
enoughtopreventthe
anionsfromcontacting
eachother.
✔Eachunitcellcontains one
Cs
+
and8 Cl
-
ions,each
contributing1/8th tothe
unitcell.
✔Eachunitcellcontains one
formulaunit.
✔Each ion residesonaseparate
simplecubic lattice resulting
intointerpenetrating SClattice
such that the cation is locatedat
the centreofthe SC unit cellof
anion and vice versa.
ZnS (Zinc Blende Structure)
(a) Zn
4S
4(Zinc Blende structure), (b) Zn
6S
6(Wurtzile structure)
✔Whensulfideions
resideatFCC
structures, resultsin
zincblendestructure.
✔Ifsulfideionsreside
atHCP,it results in
thewurtzilestructure.
Cs
+
Cl
-
(a) (b)NPTEL
Crystal structure of CsCl
Another A-X type of crystal structure (CsCl)
✔Radiusratiois0.934.It
approaches 1.
✔Co-ordinationnumberis8.
✔Higherradiusratiomeans
thecationsarelarge
enoughtopreventthe
anionsfromcontacting
eachother.
✔Eachunitcellcontains one
Cs
+
and8 Cl
-
ions,each
contributing1/8th tothe
unitcell.
✔Eachunitcellcontains one
formulaunit.
✔Each ion residesonaseparate
simplecubic lattice resulting
intointerpenetrating SClattice
such that the cation is locatedat
the centreofthe SC unit cellof
anion and vice versa.
ZnS (Zinc Blende Structure)
(a) Zn
4S
4(Zinc Blende structure), (b) Zn
6S
6(Wurtzile structure)
✔Whensulfideions
resideatFCC
structures, resultsin
zincblendestructure.
✔Ifsulfideionsreside
atHCP,it results in
thewurtzilestructure.
Cs
+
Cl
-
(a) (b)NPTEL
Zincblendestructure
ZnS (Zinc Blende Structure)
Zn
2+ S
2-
Crystal structure of ZnS (Zinc blende)
Otherexamples:SiC,ZnTe,
etc.Theyarehighlycovalent
compounds.
✔Radiusr
ofZnSis: r
cation/r
anion= 0.74/1.70 = 0.44.
✔Thes
ionsareintheclosedpack arrangement (FCC).
✔Thel
ratio indicateszinc ionsaremuchsmallerthan thesulfideions.
✔Thein
ofZinc(II)ionsintothetetrahedralholescausesthestructureto
expandsothat thesulfideionsarenotincontactwitheachother.
✔Only o
ofthetetrahedralholesareoccupiedbyzinc ions.
✔Toma
theelectrical neutrality,theremustbe4zinc ionsinthe unitcellas
thereare4 sulfideionsintheclosedpackedstructureoftheconcernedunitcell.
✔ZincBl
has(4,4)co-ordination.
✔Sulfideat
the eightcornersandsixfaces
and zinc ionsoccupythealternatetetrahedralsites inside
the unitcell.NPTEL
ZnS (Zinc Blende Structure)
Zn
2+ S
2-
Crystal structure of ZnS (Zinc blende)
Otherexamples:SiC,ZnTe,
etc.Theyarehighlycovalent
compounds.
✔Radiusr
ofZnSis: r
cation/r
anion= 0.74/1.70 = 0.44.
✔Thes
ionsareintheclosedpack arrangement (FCC).
✔Thel
ratio indicateszinc ionsaremuchsmallerthan thesulfideions.
✔Thein
ofZinc(II)ionsintothetetrahedralholescausesthestructureto
expandsothat thesulfideionsarenotincontactwitheachother.
✔Only o
ofthetetrahedralholesareoccupiedbyzinc ions.
✔Toma
theelectrical neutrality,theremustbe4zinc ionsinthe unitcellas
thereare4 sulfideionsintheclosedpackedstructureoftheconcernedunitcell.
✔ZincBl
has(4,4)co-ordination.
✔Sulfideat
the eightcornersandsixfaces
and zinc ionsoccupythealternatetetrahedralsites inside
the unitcell.NPTEL
Applicationsofceramics
Different applications of ceramics
Cutting tools
✔Forg glass,carbide,
tungsten, andceramics.
✔Forc
Siwafers.
✔For oi
drilling.
Sensors
✔ZrO
2is utilizedas an oxygensensor.
✔Ceramic gasse
nsorsdetectgaseslike
Co, H
2,NO
x, CH
4, CO
2,etc.
✔Usedin h
andtemperature
sensor.
Refractories
✔Usedinhi-temperature furnaces.
✔Magnesia, c
hrome-magnesia,
forsterite-magnesia,spinel-magnesia,
anddead-burned dolomiteare
famous examples ofrefractories.
Other Applications
✔Advancedc areusedfor automobileengines. Examples:Si
3N
4,SiCand
ZrO
2.
✔Ceramicsa
usedinfoodprocessingequipment,aerospaceturbineblades,nuclearfuel
rods,lightweightarmor,stealthcoatings,etc.NPTEL
Different applications of ceramics
Cutting tools
✔Forg glass,carbide,
tungsten, andceramics.
✔Forc
Siwafers.
✔For oi
drilling.
Sensors
✔ZrO
2is utilizedas an oxygensensor.
✔Ceramic gasse
nsorsdetectgaseslike
Co, H
2,NO
x, CH
4, CO
2,etc.
✔Usedin h
andtemperature
sensor.
Refractories
✔Usedinhi-temperature furnaces.
✔Magnesia, c
hrome-magnesia,
forsterite-magnesia,spinel-magnesia,
anddead-burned dolomiteare
famous examples ofrefractories.
Other Applications
✔Advancedc areusedfor automobileengines. Examples:Si
3N
4,SiCand
ZrO
2.
✔Ceramicsa
usedinfoodprocessingequipment,aerospaceturbineblades,nuclearfuel
rods,lightweightarmor,stealthcoatings,etc.NPTEL
Composites
Let us now discuss another type of functional material
i.e. Composites
Somebasicfieldswherecompositesareused:
Dieselpistons,Brake-shoesandpads,Tires,Aircrafts,coatings,toothfillers,etc.
Application of composites NPTEL
Let us now discuss another type of functional material
i.e. Composites
Somebasicfieldswherecompositesareused:
Dieselpistons,Brake-shoesandpads,Tires,Aircrafts,coatings,toothfillers,etc.
Application of composites NPTEL
Definition
Compositeiscomposed oftwoormoredistinctphases (matrix phaseanddispersedphase)and has bulkproperties
significantlydifferent fromthoseofanyoftheconstituents.
⮚Composites are combinations of two or more materials in which one of the materials is called the reinforcing phase.
⮚The reinforcing phase is in the form of fibers, sheets, or particles, and is embedded in the other materials called the matrix
ph
ase.
⮚The reinforcing and matrix materials can be metal, ceramic, or polymer. The dispersed phase is usually stronger than the
ma
trix, therefore it is called the reinforcing phase.
Significantpointsaboutcomposites
Matrix Reinforcement Composite NPTEL
Compositeiscomposed oftwoormoredistinctphases (matrix phaseanddispersedphase)and has bulkproperties
significantlydifferent fromthoseofanyoftheconstituents.
⮚Composites are combinations of two or more materials in which one of the materials is called the reinforcing phase.
⮚The reinforcing phase is in the form of fibers, sheets, or particles, and is embedded in the other materials called the matrix
ph
ase.
⮚The reinforcing and matrix materials can be metal, ceramic, or polymer. The dispersed phase is usually stronger than the
ma
trix, therefore it is called the reinforcing phase.
Significantpointsaboutcomposites
Matrix Reinforcement Composite NPTEL
Classificationofcomposites
⮚Metal Ma Composites (MMC)arecomposed of ametallic matrix (aluminum,magnesium, iron,cobalt, copper)anda
dispersedceramic(oxides, carbides) ormetallic(lead,tungsten,molybdenum) phase.
⮚PolymerMa
trixComposites (PMC)arecomposed of amatrixfromthermoset (UnsaturatedPolyester(UP), Epoxiy (EP))
orthermoplastic(Polycarbonate (PC),Polyvinylchloride,NylonPolysterene)andembeddedglass, carbon,steelor Kevlar
fibers(dispersedphase).
⮚CeramicMa
trixComposites (CMC)arecomposed of aceramic matrixandembedded fibers
orwhiskersofothermaterials(dispersedphase).
Classification of composites
Metal matrix
composite (MMC)
Ceramic matrix
composite (CMC)
Polymer matrix
composite (PMC)
Based onthematrix material,compositesareclassified intothreetypes.NPTEL
⮚Metal Ma Composites (MMC)arecomposed of ametallic matrix (aluminum,magnesium, iron,cobalt, copper)anda
dispersedceramic(oxides, carbides) ormetallic(lead,tungsten,molybdenum) phase.
⮚PolymerMa
trixComposites (PMC)arecomposed of amatrixfromthermoset (UnsaturatedPolyester(UP), Epoxiy (EP))
orthermoplastic(Polycarbonate (PC),Polyvinylchloride,NylonPolysterene)andembeddedglass, carbon,steelor Kevlar
fibers(dispersedphase).
⮚CeramicMa
trixComposites (CMC)arecomposed of aceramic matrixandembedded fibers
orwhiskersofothermaterials(dispersedphase).
Classification of composites
Metal matrix
composite (MMC)
Ceramic matrix
composite (CMC)
Polymer matrix
composite (PMC)
Based onthematrix material,compositesareclassified intothreetypes.NPTEL
Ceramicmatrixcomposite(CMC)
Component of CMCs
Fibers MatrixInterphases
Why do I need to move to ceramic matrix composite (CMC) from ceramic?
✔Ceramicsh recently becomean ideal candidate for applicationsthatrequire(i)
hightemperature, (ii)highchemical resistivity, (iii)oxidationresistance,and high
(iv)thermal conductivity.
✔Theappl
arelimitedbythe inherentbrittlenatureofceramics.
✔Fiber-
reinforcedCMCs mayovercometheseissues.
✔Combining different
ceramic matrix
materials, with suitable
fibers,leadstonew
propertiesthatcan be
tailoredforinteresting
applications.
Matrix: The matrix binds the fiber reinforcement, transfers loads between fibers, gives the
composite component its net shape, and determines its surface quality.
Fibers: Fibers provide strength and structure for the ceramic composite. Fibers exist in CMCs
as unidirectional tow and as both two-dimensional (2D) and three -dimensional (3D) woven
fabrics in continuous fiber-reinforced CMCs (CF-CMCs).NPTEL
Component of CMCs
Fibers MatrixInterphases
Why do I need to move to ceramic matrix composite (CMC) from ceramic?
✔Ceramicsh recently becomean ideal candidate for applicationsthatrequire(i)
hightemperature, (ii)highchemical resistivity, (iii)oxidationresistance,and high
(iv)thermal conductivity.
✔Theappl
arelimitedbythe inherentbrittlenatureofceramics.
✔Fiber-
reinforcedCMCs mayovercometheseissues.
✔Combining different
ceramic matrix
materials, with suitable
fibers,leadstonew
propertiesthatcan be
tailoredforinteresting
applications.
Matrix: The matrix binds the fiber reinforcement, transfers loads between fibers, gives the
composite component its net shape, and determines its surface quality.
Fibers: Fibers provide strength and structure for the ceramic composite. Fibers exist in CMCs
as unidirectional tow and as both two-dimensional (2D) and three -dimensional (3D) woven
fabrics in continuous fiber-reinforced CMCs (CF-CMCs).NPTEL
Interphase:The interphaseprovides a weak interfacial bondtothefiberandthematrix, allowingforslippingandenergy
dispersionofthemechanicalstressesexperiencedinthecomposite.
Fibers
Oxides Non-oxides
Silicon dioxide, alumina,
boria, and zirconia.
Silicon carbide, silicon nitride, and carbon
Boron, titanium, and zirconium
Typical synthesis methods of fibers include:
(i) Spinning the fiber from a liquid, or organic precursors.
(ii) Chemical vapor deposition of the ceramics on an existing fiber substrate.
Ceramicmatrixcomposite(CMC)NPTEL
dispersionofthemechanicalstressesexperiencedinthecomposite.
Fibers
Oxides Non-oxides
Silicon dioxide, alumina,
boria, and zirconia.
Silicon carbide, silicon nitride, and carbon
Boron, titanium, and zirconium
Typical synthesis methods of fibers include:
(i) Spinning the fiber from a liquid, or organic precursors.
(ii) Chemical vapor deposition of the ceramics on an existing fiber substrate.
Ceramicmatrixcomposite(CMC)NPTEL
Matrix
Oxides Non-oxides
Alumina, mullite,
silica and zirconia.
Silicon carbide, silicon nitride,carbon.
✔Matrices a designedtohave highthermal stability,witha
similar thermalexpansioncoefficienttothefiberanda low
density.
✔Thema
provides both protection forthefiberand
interphaseas well as ameansbywhichenergyfrom
mechanicalstressescandispersethrough thecomposite.
✔Theco
ofthermalexpansion (CTE)playsavery
importantroleintheselectionofmatrix material.
✔Large di
inCTEbetweenthefiberand thematrix
canresultinstresses,cracking,andcomposite damage
when theCMCisbothheatedandcooled.
✔Lowth
expansionin materials likeC–C,andSiC–SiC
compositesresultinreducedexpansion.
✔Oxidema
arestabletolowertemperaturesthan
typicaloxidematrices,butsintereasilyforeaseof
productionandprovideinherentoxidationresistance.
✔Theya
limitedbytheirhigherthermalexpansion
coefficients as well asthelossofhighstrengthand
toughnessatelevatedtemperatures.
✔Thema
non-oxidesystemsisalsodesignedto
provide oxidationresistancetopreventdamagetoboth
the interphase andfiber.
Methods of synthesis
❑Sol-gelmethod.
❑Chemical vapor
infiltration(CVI).
❑Chemical vapor
deposition,etc.
Ceramicmatrixcomposite(CMC)NPTEL
Oxides Non-oxides
Alumina, mullite,
silica and zirconia.
Silicon carbide, silicon nitride,carbon.
✔Matrices a designedtohave highthermal stability,witha
similar thermalexpansioncoefficienttothefiberanda low
density.
✔Thema
provides both protection forthefiberand
interphaseas well as ameansbywhichenergyfrom
mechanicalstressescandispersethrough thecomposite.
✔Theco
ofthermalexpansion (CTE)playsavery
importantroleintheselectionofmatrix material.
✔Large di
inCTEbetweenthefiberand thematrix
canresultinstresses,cracking,andcomposite damage
when theCMCisbothheatedandcooled.
✔Lowth
expansionin materials likeC–C,andSiC–SiC
compositesresultinreducedexpansion.
✔Oxidema
arestabletolowertemperaturesthan
typicaloxidematrices,butsintereasilyforeaseof
productionandprovideinherentoxidationresistance.
✔Theya
limitedbytheirhigherthermalexpansion
coefficients as well asthelossofhighstrengthand
toughnessatelevatedtemperatures.
✔Thema
non-oxidesystemsisalsodesignedto
provide oxidationresistancetopreventdamagetoboth
the interphase andfiber.
Methods of synthesis
❑Sol-gelmethod.
❑Chemical vapor
infiltration(CVI).
❑Chemical vapor
deposition,etc.
Ceramicmatrixcomposite(CMC)NPTEL
Chemical vapour infiltration (CVI) technique for fabricating
SiC/SiC
✔The s procedures ofceramic matrixcompositesinvolvedifferent methods.
Methods of synthesis
❑Sol- method.
❑Chemical v
infiltration(CVI).
❑Liquidph
infiltration(LPI).
❑Polymerin
(PI).
❑Thermalc
-linking followed bypyrolysis.
❑Hotp
sinteringtechniques.
❑Exfoliation fol
lowed by ballmilling, etc.
Synthesisofceramicmatrixcomposite(CMC)
✔Amongtheabovementioned technique
themostcommonisChemicalvapor
infiltration(CVI).
Silicaremoval
(HFtreatment)
Silicaremoval
(HFtreatment)
✔Thed ofthe
mesoporoussilica(SBA-
15),istunedviachemical
vapour deposition (CVD)
technique.
✔SiC ha
grown onthe
SBA-15template.
✔SBA-
templatehasbeen
removedviahydrofluoric
acidtreatment.NPTEL
SiC/SiC
✔The s procedures ofceramic matrixcompositesinvolvedifferent methods.
Methods of synthesis
❑Sol- method.
❑Chemical v
infiltration(CVI).
❑Liquidph
infiltration(LPI).
❑Polymerin
(PI).
❑Thermalc
-linking followed bypyrolysis.
❑Hotp
sinteringtechniques.
❑Exfoliation fol
lowed by ballmilling, etc.
Synthesisofceramicmatrixcomposite(CMC)
✔Amongtheabovementioned technique
themostcommonisChemicalvapor
infiltration(CVI).
Silicaremoval
(HFtreatment)
Silicaremoval
(HFtreatment)
✔Thed ofthe
mesoporoussilica(SBA-
15),istunedviachemical
vapour deposition (CVD)
technique.
✔SiC ha
grown onthe
SBA-15template.
✔SBA-
templatehasbeen
removedviahydrofluoric
acidtreatment.NPTEL
ApplicationsofCMC
✔Applications ofc eramic matrixcomposite (CMC)coversa large range of fieldsinourdailylife.
❑Aeronauticala
ndautomotivepurposes
❑Orthopedica
nddentalimplants
❑Petroleumhy
dro-treatments
❑Thepot
inchemicalwarfare
❑Solarc
❑Humidityse
❑Electronicappl
ications
❑Electrolytefors
olidoxidefuelcell
❑High-
speedcuttingtool applications
❑Structuresfor gast
urbine engines
❑Electricala
thermal insulatorsNPTEL
✔Applications ofc eramic matrixcomposite (CMC)coversa large range of fieldsinourdailylife.
❑Aeronauticala
ndautomotivepurposes
❑Orthopedica
nddentalimplants
❑Petroleumhy
dro-treatments
❑Thepot
inchemicalwarfare
❑Solarc
❑Humidityse
❑Electronicappl
ications
❑Electrolytefors
olidoxidefuelcell
❑High-
speedcuttingtool applications
❑Structuresfor gast
urbine engines
❑Electricala
thermal insulatorsNPTEL
❖Ceramicsexistindifferentcrystalstructures.
❖Theyha
widerangeoftunablephysicalandchemicalproperties.NPTEL
❖Theyha
widerangeoftunablephysicalandchemicalproperties.NPTEL
❑O. G Diaza,G.GarciaLuna, Z.Liao,andD. Axinte,“Thenewchallengesof machiningCeramicMatrixComposites
(CMCs): review of surfaceintegrity,”InternationalJournal ofMachineToolsand Manufacture, vol. 139, pp. 24– 36, 2019.
❑F.Z
H. AiminPang, Z. Kechao, and Y.Haitang,“Researchprogress ofceramicmatrixcomposites forhightemperature
stealthtechnologybasedonmulti-scale collaborativedesign,”JournalofMaterialsResearchandTechnology,vol. 18,no.
2022, pp. 2770–2783.
❑Advanced Ce
ramicMaterialsbyAshutoshTiwari,Rosario A. Gerhardt and Magdalena Szutkowska.
❑Physicsof F
MaterialsbyHasseFredriksson andUlaAkerlind.
❑Handbook of A
dvancedCeramicsand Composites byYashwantR.Mahajanand Roy Johnson.NPTEL
(CMCs): review of surfaceintegrity,”InternationalJournal ofMachineToolsand Manufacture, vol. 139, pp. 24– 36, 2019.
❑F.Z
H. AiminPang, Z. Kechao, and Y.Haitang,“Researchprogress ofceramicmatrixcomposites forhightemperature
stealthtechnologybasedonmulti-scale collaborativedesign,”JournalofMaterialsResearchandTechnology,vol. 18,no.
2022, pp. 2770–2783.
❑Advanced Ce
ramicMaterialsbyAshutoshTiwari,Rosario A. Gerhardt and Magdalena Szutkowska.
❑Physicsof F
MaterialsbyHasseFredriksson andUlaAkerlind.
❑Handbook of A
dvancedCeramicsand Composites byYashwantR.Mahajanand Roy Johnson.NPTEL
Thank youNPTEL
Physics of Functional Materials & Devices
Prof. Amreesh Chandra
Department of Physics, IIT KHARAGPUR
Module 01: Introduction to Functional Materials
Lecture 02 : Ceramics and CompositesNPTEL
Prof. Amreesh Chandra
Department of Physics, IIT KHARAGPUR
Module 01: Introduction to Functional Materials
Lecture 02 : Ceramics and CompositesNPTEL
❑Definitiona ndclassificationofcomposites.
❑Applicationsofc
ompositesNPTEL
❑Applicationsofc
ompositesNPTEL
Inthepreviouslecture,weintroduced: Ceramics.
Definitions:Aceramicisaninorganicmaterial,whichispreparedathightemperatures.
Ceramicscanbecrystalline,glassy,orbothcrystallineandglassy.
Examples:clay,bricks,glass,tiles,cement,dielectric,oxides,cladding,shields,etc.
CeramicsNPTEL
Definitions:Aceramicisaninorganicmaterial,whichispreparedathightemperatures.
Ceramicscanbecrystalline,glassy,orbothcrystallineandglassy.
Examples:clay,bricks,glass,tiles,cement,dielectric,oxides,cladding,shields,etc.
CeramicsNPTEL
Composites
Let us now discuss another type of functional material
i.e. Composites
Somebasicfieldswherecompositesareused:
Dieselpistons,Brake-shoesandpads,Tires,Aircrafts,coatings,toothfillers,etc.
Application of composites NPTEL
Let us now discuss another type of functional material
i.e. Composites
Somebasicfieldswherecompositesareused:
Dieselpistons,Brake-shoesandpads,Tires,Aircrafts,coatings,toothfillers,etc.
Application of composites NPTEL
Definition
Compositeiscomposed oftwoormoredistinctphases (matrix phaseanddispersedphase)and has bulkproperties
significantlydifferent fromthoseofanyoftheconstituents.
⮚Composites are combinations of two or more materials in which one of the materials is called the reinforcing phase.
⮚The reinforcing phase is in the form of fibers, sheets, or particles, and is embedded in the other materials called the matrix
ph
ase.
⮚The reinforcing and matrix materials can be metal, ceramic, or polymer. The dispersed phase is usually stronger than the
ma
trix, therefore it is called the reinforcing phase.
Significantpointsaboutcomposites
Matrix Reinforcement Composite NPTEL
Compositeiscomposed oftwoormoredistinctphases (matrix phaseanddispersedphase)and has bulkproperties
significantlydifferent fromthoseofanyoftheconstituents.
⮚Composites are combinations of two or more materials in which one of the materials is called the reinforcing phase.
⮚The reinforcing phase is in the form of fibers, sheets, or particles, and is embedded in the other materials called the matrix
ph
ase.
⮚The reinforcing and matrix materials can be metal, ceramic, or polymer. The dispersed phase is usually stronger than the
ma
trix, therefore it is called the reinforcing phase.
Significantpointsaboutcomposites
Matrix Reinforcement Composite NPTEL
Classificationofcomposites
⮚Metal Ma Composites (MMC)arecomposed of ametallic matrix (aluminum,magnesium, iron,cobalt, copper)anda
dispersedceramic(oxides, carbides) ormetallic(lead,tungsten,molybdenum) phase.
⮚PolymerMa
trixComposites (PMC)arecomposed of amatrixfromthermoset (UnsaturatedPolyester(UP), Epoxiy (EP))
orthermoplastic(Polycarbonate (PC),Polyvinylchloride,NylonPolysterene)andembeddedglass, carbon,steelor Kevlar
fibers(dispersedphase).
⮚CeramicMa
trixComposites (CMC)arecomposed of aceramic matrixandembedded fibers
orwhiskersofothermaterials(dispersedphase).
Classification of composites
Metal matrix
composite (MMC)
Ceramic matrix
composite (CMC)
Polymer matrix
composite (PMC)
Based onthematrix material,compositesareclassified intothreetypes.NPTEL
⮚Metal Ma Composites (MMC)arecomposed of ametallic matrix (aluminum,magnesium, iron,cobalt, copper)anda
dispersedceramic(oxides, carbides) ormetallic(lead,tungsten,molybdenum) phase.
⮚PolymerMa
trixComposites (PMC)arecomposed of amatrixfromthermoset (UnsaturatedPolyester(UP), Epoxiy (EP))
orthermoplastic(Polycarbonate (PC),Polyvinylchloride,NylonPolysterene)andembeddedglass, carbon,steelor Kevlar
fibers(dispersedphase).
⮚CeramicMa
trixComposites (CMC)arecomposed of aceramic matrixandembedded fibers
orwhiskersofothermaterials(dispersedphase).
Classification of composites
Metal matrix
composite (MMC)
Ceramic matrix
composite (CMC)
Polymer matrix
composite (PMC)
Based onthematrix material,compositesareclassified intothreetypes.NPTEL
Ceramicmatrixcomposite(CMC)
Why do I need to move to ceramic matrix composite (CMC) from ceramic?
✔Ceramicsha verecently becomean ideal candidate for applicationsthatrequire(i)hightemperature, (ii)highchemical
resistivity, (iii)oxidationresistance,and high(iv)thermal conductivity.
✔Theappl
arelimitedbythe inherentbrittlenatureofceramics.
✔Fiber-
reinforcedCMCs mayovercometheseissues.
✔Combining differentceramic matrix materials, with suitablefibers,leadstonew
propertiesthatcan betailoredforinterestingapplications.NPTEL
Why do I need to move to ceramic matrix composite (CMC) from ceramic?
✔Ceramicsha verecently becomean ideal candidate for applicationsthatrequire(i)hightemperature, (ii)highchemical
resistivity, (iii)oxidationresistance,and high(iv)thermal conductivity.
✔Theappl
arelimitedbythe inherentbrittlenatureofceramics.
✔Fiber-
reinforcedCMCs mayovercometheseissues.
✔Combining differentceramic matrix materials, with suitablefibers,leadstonew
propertiesthatcan betailoredforinterestingapplications.NPTEL
Ceramicmatrixcomposite(CMC)
Component of CMCs
Fibers MatrixInterphases
Matrix: The matrix binds the fiber reinforcement, transfers loads between fibers, gives the composite component its net
shape, and determines its surface quality.
Fibers: Fibers provide strength and structure for the ceramic composite. Fibers exist in CMCs as unidirectional tow and
as both two-dimensional (2D) and three -dimensional (3D) woven fabrics in continuous fiber-reinforced CMCs (CF-
CMCs).NPTEL
Component of CMCs
Fibers MatrixInterphases
Matrix: The matrix binds the fiber reinforcement, transfers loads between fibers, gives the composite component its net
shape, and determines its surface quality.
Fibers: Fibers provide strength and structure for the ceramic composite. Fibers exist in CMCs as unidirectional tow and
as both two-dimensional (2D) and three -dimensional (3D) woven fabrics in continuous fiber-reinforced CMCs (CF-
CMCs).NPTEL
Interphase:
Theinterphase providesaweakinterfacialbondtothefiberand thematrix,
allowingforslippingandenergydispersionofthemechanicalstressesexperienced
inthecomposite.
Ceramicmatrixcomposite(CMC)NPTEL
Theinterphase providesaweakinterfacialbondtothefiberand thematrix,
allowingforslippingandenergydispersionofthemechanicalstressesexperienced
inthecomposite.
Ceramicmatrixcomposite(CMC)NPTEL
Ceramicmatrixcomposite(CMC)
Fibers
Oxides Non-oxides
Silicon dioxide, alumina,
boria, and zirconia.
Silicon carbide, silicon nitride, and carbon
Boron, titanium, and zirconium
Typical synthesis methods of fibers include:
(i) Spinning the fiber from a liquid, or organic precursors.
(ii) Chemical vapor deposition of the ceramics on an existing fiber substrate. NPTEL
Fibers
Oxides Non-oxides
Silicon dioxide, alumina,
boria, and zirconia.
Silicon carbide, silicon nitride, and carbon
Boron, titanium, and zirconium
Typical synthesis methods of fibers include:
(i) Spinning the fiber from a liquid, or organic precursors.
(ii) Chemical vapor deposition of the ceramics on an existing fiber substrate. NPTEL
Matrix
Oxides Non-oxides
Alumina, mullite,
silica and zirconia.
Silicon carbide, silicon nitride,carbon.
Ceramicmatrixcomposite(CMC)NPTEL
Oxides Non-oxides
Alumina, mullite,
silica and zirconia.
Silicon carbide, silicon nitride,carbon.
Ceramicmatrixcomposite(CMC)NPTEL
✔Matrices aredesignedtohavehighthermal stability,withasimilar thermalexpansioncoefficienttothefiberanda low
density.
✔Thematrixprovides both protection forthefiberand interphaseas well as ameansbywhichenergyfrommechanical
stressescandispersethrough thecomposite.
✔Thecoefficientofthermalexpansion (CTE) plays averyimportantroleintheselectionofmatrix material.
✔Large differencesinCTEbetweenthefiberand thematrixcanresultinstresses,cracking,andcomposite damagewhen
theCMCisbothheatedandcooled.
✔Lowthermalexpansionin materials likeC–C,and SiC–SiCcompositesresultinreducedexpansion.
✔Oxidematricesarestabletolowertemperaturesthantypicaloxidematrices,butsinter
easilyforeaseof productionandprovideinherentoxidationresistance.
✔Theyarelimitedbytheirhigherthermalexpansioncoefficientsas well asthelossof
highstrengthand toughnessatelevatedtemperatures.
✔Thematrix innon-oxidesystemsisalsodesignedtoprovide oxidationresistanceto
preventdamagetoboththe interphase andfiber.
Ceramicmatrixcomposite(CMC)NPTEL
density.
✔Thematrixprovides both protection forthefiberand interphaseas well as ameansbywhichenergyfrommechanical
stressescandispersethrough thecomposite.
✔Thecoefficientofthermalexpansion (CTE) plays averyimportantroleintheselectionofmatrix material.
✔Large differencesinCTEbetweenthefiberand thematrixcanresultinstresses,cracking,andcomposite damagewhen
theCMCisbothheatedandcooled.
✔Lowthermalexpansionin materials likeC–C,and SiC–SiCcompositesresultinreducedexpansion.
✔Oxidematricesarestabletolowertemperaturesthantypicaloxidematrices,butsinter
easilyforeaseof productionandprovideinherentoxidationresistance.
✔Theyarelimitedbytheirhigherthermalexpansioncoefficientsas well asthelossof
highstrengthand toughnessatelevatedtemperatures.
✔Thematrix innon-oxidesystemsisalsodesignedtoprovide oxidationresistanceto
preventdamagetoboththe interphase andfiber.
Ceramicmatrixcomposite(CMC)NPTEL
Chemical vapour infiltration (CVI) technique for fabricating
SiC/SiC
✔The s procedures ofceramic matrixcompositesinvolvedifferent methods.
Methods of synthesis
❑Sol- method.
❑Chemical v
infiltration(CVI).
❑Liquidph
infiltration(LPI).
❑Polymerin
(PI).
❑Thermalc
-linking followed bypyrolysis.
❑Hotp
sinteringtechniques.
❑Exfoliation fol
lowed by ballmilling, etc.
Synthesisofceramicmatrixcomposite(CMC)
✔Amongtheabovementioned technique
themostcommonisChemicalvapor
infiltration(CVI).
Silicaremoval
(HFtreatment)
Silicaremoval
(HFtreatment)
✔Thed ofthe
mesoporoussilica(SBA-
15),istunedviachemical
vapour deposition (CVD)
technique.
✔SiC ha
grown onthe
SBA-15template.
✔SBA-
templatehasbeen
removedviahydrofluoric
acidtreatment.NPTEL
SiC/SiC
✔The s procedures ofceramic matrixcompositesinvolvedifferent methods.
Methods of synthesis
❑Sol- method.
❑Chemical v
infiltration(CVI).
❑Liquidph
infiltration(LPI).
❑Polymerin
(PI).
❑Thermalc
-linking followed bypyrolysis.
❑Hotp
sinteringtechniques.
❑Exfoliation fol
lowed by ballmilling, etc.
Synthesisofceramicmatrixcomposite(CMC)
✔Amongtheabovementioned technique
themostcommonisChemicalvapor
infiltration(CVI).
Silicaremoval
(HFtreatment)
Silicaremoval
(HFtreatment)
✔Thed ofthe
mesoporoussilica(SBA-
15),istunedviachemical
vapour deposition (CVD)
technique.
✔SiC ha
grown onthe
SBA-15template.
✔SBA-
templatehasbeen
removedviahydrofluoric
acidtreatment.NPTEL
ApplicationsofCMC
✔Applications ofc eramic matrixcomposite (CMC)coversa large range of fieldsinourdailylife.
❑Aeronauticala
ndautomotivepurposes
❑Orthopedica
nddentalimplants
❑Petroleumhy
dro-treatments
❑Thepot
inchemicalwarfare
❑Solarc
❑Humidityse
❑Electronicappl
ications
❑Electrolytefors
olidoxidefuelcell
❑High-
speedcuttingtool applications
❑Structuresfor gast
urbine engines
❑Electricala
thermal insulatorsNPTEL
✔Applications ofc eramic matrixcomposite (CMC)coversa large range of fieldsinourdailylife.
❑Aeronauticala
ndautomotivepurposes
❑Orthopedica
nddentalimplants
❑Petroleumhy
dro-treatments
❑Thepot
inchemicalwarfare
❑Solarc
❑Humidityse
❑Electronicappl
ications
❑Electrolytefors
olidoxidefuelcell
❑High-
speedcuttingtool applications
❑Structuresfor gast
urbine engines
❑Electricala
thermal insulatorsNPTEL
❖Compositema terialswereintroduced.
❖Therear
differenttypesofcomposites,whichwerealsodiscussed.
❖Thecera
based composites arefindinglotof applicationsandarequiterelevantto
ourcourse.
❖Itiscl
thatcompositeshavealargenumberofapplications.NPTEL
❖Therear
differenttypesofcomposites,whichwerealsodiscussed.
❖Thecera
based composites arefindinglotof applicationsandarequiterelevantto
ourcourse.
❖Itiscl
thatcompositeshavealargenumberofapplications.NPTEL
❑O. G Diaza,G.GarciaLuna, Z.Liao,andD. Axinte,“Thenewchallengesof machiningCeramicMatrixComposites
(CMCs): review of surfaceintegrity,”InternationalJournal ofMachineToolsand Manufacture, vol. 139, pp. 24– 36, 2019.
❑F.Z
H. AiminPang, Z. Kechao, and Y.Haitang,“Researchprogress ofceramicmatrixcomposites forhightemperature
stealthtechnologybasedonmulti-scale collaborativedesign,”JournalofMaterialsResearchandTechnology,vol. 18,no.
2022, pp. 2770–2783.
❑Advanced Ce
ramicMaterialsbyAshutoshTiwari,Rosario A. Gerhardt and Magdalena Szutkowska.
❑Physicsof F
MaterialsbyHasseFredriksson andUlaAkerlind.
❑Handbook of A
dvancedCeramicsand Composites byYashwantR.Mahajanand Roy Johnson.NPTEL
(CMCs): review of surfaceintegrity,”InternationalJournal ofMachineToolsand Manufacture, vol. 139, pp. 24– 36, 2019.
❑F.Z
H. AiminPang, Z. Kechao, and Y.Haitang,“Researchprogress ofceramicmatrixcomposites forhightemperature
stealthtechnologybasedonmulti-scale collaborativedesign,”JournalofMaterialsResearchandTechnology,vol. 18,no.
2022, pp. 2770–2783.
❑Advanced Ce
ramicMaterialsbyAshutoshTiwari,Rosario A. Gerhardt and Magdalena Szutkowska.
❑Physicsof F
MaterialsbyHasseFredriksson andUlaAkerlind.
❑Handbook of A
dvancedCeramicsand Composites byYashwantR.Mahajanand Roy Johnson.NPTEL
Thank youNPTEL
Physics of Functional Materials & Devices
Prof. Amreesh Chandra
Department of Physics, IIT KHARAGPUR
Module01: Introduction to Functionality and Functional Materials
Lecture 03 : PolymersNPTEL
Prof. Amreesh Chandra
Department of Physics, IIT KHARAGPUR
Module01: Introduction to Functionality and Functional Materials
Lecture 03 : PolymersNPTEL
❑Definition of polymers
❑Polymerization
❑Classification and applications of various polymersNPTEL
❑Polymerization
❑Classification and applications of various polymersNPTEL
What are polymers?
❖The word polymer is derived from the classical Greek words poly meaning “many” and meres meaning “parts”.
❖Thus, a polymer is a large molecule (macromolecule) built up by the repetition of small chemical units.
C
onsider the following example of a polymer:
nCH
2=CH -CH
2-CH-
n
Styrene (Monomer) Polystyrene (Polymer)
❖Monomer: Any molecule that can be converted to a polymer by combining with other
mol
ecules of the same or different type.
Examples of polymers are cellulose, honey, silk, rubber, polyethylene, polyvinyl chloride nylon, etc.
❖Polymerization: Polymerization is a process of reacting monomer molecules together in a
chemical reaction to form polymer chains or three-dimensional networks.NPTEL
❖The word polymer is derived from the classical Greek words poly meaning “many” and meres meaning “parts”.
❖Thus, a polymer is a large molecule (macromolecule) built up by the repetition of small chemical units.
C
onsider the following example of a polymer:
nCH
2=CH -CH
2-CH-
n
Styrene (Monomer) Polystyrene (Polymer)
❖Monomer: Any molecule that can be converted to a polymer by combining with other
mol
ecules of the same or different type.
Examples of polymers are cellulose, honey, silk, rubber, polyethylene, polyvinyl chloride nylon, etc.
❖Polymerization: Polymerization is a process of reacting monomer molecules together in a
chemical reaction to form polymer chains or three-dimensional networks.NPTEL
What is polymerization?
✔Polymerizationis a p rocessofreactingmonomermoleculestogetherina chemical reactiontoformpolymerchains
or three-dimensional networks.
❖Usuallyatleas
t 100monomermoleculesmust be combined tomake aproduct that hascertainuniquephysical
properties—suchas elasticity,hightensilestrength, or theabilityto form fibres—that differentiateitfrom the
startingmaterials.
❖Polymerizationisi
mportantbecause it allowsthecreationof newchemicals likeglycogen,cellulose,and fattyacids.
Let us now discuss them in a bit detail !NPTEL
✔Polymerizationis a p rocessofreactingmonomermoleculestogetherina chemical reactiontoformpolymerchains
or three-dimensional networks.
❖Usuallyatleas
t 100monomermoleculesmust be combined tomake aproduct that hascertainuniquephysical
properties—suchas elasticity,hightensilestrength, or theabilityto form fibres—that differentiateitfrom the
startingmaterials.
❖Polymerizationisi
mportantbecause it allowsthecreationof newchemicals likeglycogen,cellulose,and fattyacids.
Let us now discuss them in a bit detail !NPTEL
Polymers can be classified based on the origin of the polymer, polymer structure, polymerization mechanism, preparative
techniques, or thermal behavior.
Classification of polymers
Polymers
Origin Structure Force of attractionPolymerization
•Fibers
•Plastics
•Elastomers
•Condensation
•Addition
•Ring-opening
Thermal behaviour
•Thermoplastic
•Thermoset
•Natural
•Synthetic
•Semi-s
•Linear, Branched
o
r Cross-linked
•Amorphous
or
crystalline
•Semi-s
•Homopolymer or
C
opolymerNPTEL
techniques, or thermal behavior.
Classification of polymers
Polymers
Origin Structure Force of attractionPolymerization
•Fibers
•Plastics
•Elastomers
•Condensation
•Addition
•Ring-opening
Thermal behaviour
•Thermoplastic
•Thermoset
•Natural
•Synthetic
•Semi-s
•Linear, Branched
o
r Cross-linked
•Amorphous
or
crystalline
•Semi-s
•Homopolymer or
C
opolymerNPTEL
“In some cases, naturally occurring polymers can also be produced synthetically. Example
is natural (Hevea) rubber, known as polyisoprene in its synthetic form.”
1. Classification based on the origin of the polymers: Polymers may either be natural, synthetic or semi -synthetic.
Synthetic polymers
Synthetic polymers are human- made polymers. Examples: Polyethylene, Polyvinyl chloride
nylon, etc.
Polymers
Naturalpolymers
•Enzymes, nuc
leicacids, proteins, carbohydrates arepolymers ofnatural origin. Their
structuresarenormallyverycomplex.
•Starch,ce
llulose are examplesof polymers ofplantorigin (natural) buthaverelatively
simplerstructures than those of enzymes or proteins.
Semi-synthetic polymers
Semi-synthetic polymers are polymers that are derived from
nature itself but are made to undergo chemical processes to enhance their quality. Examples: Rayon, vulcanized rubber, gun cotton, etc.NPTEL
is natural (Hevea) rubber, known as polyisoprene in its synthetic form.”
1. Classification based on the origin of the polymers: Polymers may either be natural, synthetic or semi -synthetic.
Synthetic polymers
Synthetic polymers are human- made polymers. Examples: Polyethylene, Polyvinyl chloride
nylon, etc.
Polymers
Naturalpolymers
•Enzymes, nuc
leicacids, proteins, carbohydrates arepolymers ofnatural origin. Their
structuresarenormallyverycomplex.
•Starch,ce
llulose are examplesof polymers ofplantorigin (natural) buthaverelatively
simplerstructures than those of enzymes or proteins.
Semi-synthetic polymers
Semi-synthetic polymers are polymers that are derived from
nature itself but are made to undergo chemical processes to enhance their quality. Examples: Rayon, vulcanized rubber, gun cotton, etc.NPTEL
Applications of natural, synthetic and semi-synthetic polymers
Natural Polymers
✔Papers
✔Pharmaceuticals
✔Foods
✔Imaging agents
Sy
nthetic Polymers
✔Plastic bags and film wraps
✔Pipes, and flooring purposes
✔Packaging
✔Electrical insulations
Semi-synthetic Polymers
✔Tyre industry
✔ExplosivesNPTEL
Natural Polymers
✔Papers
✔Pharmaceuticals
✔Foods
✔Imaging agents
Sy
nthetic Polymers
✔Plastic bags and film wraps
✔Pipes, and flooring purposes
✔Packaging
✔Electrical insulations
Semi-synthetic Polymers
✔Tyre industry
✔ExplosivesNPTEL
2. Classification based on the structure
i.Linear, Branched and Cross- linked polymer
a)Linearpolymer: Alinearpolymerconsistsofa singlecontinuouschainofrepeating units.Theatomsbondedtoeachothercovalently
formsthe backboneofthepolymer.Examples: Polyethylene, PVC,polystyrene, polyamides,etc.
c)Cross-linked polymers:Cross-linked polymers are polymers in which monomer units are cross-linked
together to form a three-dimensional network polymer. Examples: polyester fiberglass, polyurethanes
used as coatings, adhesives, vulcanized rubber, etc.
b)Branchedpolymer: Abranchedpolymerisamacromoleculemadefromthepolymerizationof
monomersand hasabranchedstructure.Thepropertiesofthese polymersaremainlyaffectedby
the amountofbranching.Examples:low-densitypolyethylene(LDPE), high- densitypolyethylene
(HDPE),and polypropylene(PP).
Linear polymer Branched polymer Cross-lined polymerNPTEL
i.Linear, Branched and Cross- linked polymer
a)Linearpolymer: Alinearpolymerconsistsofa singlecontinuouschainofrepeating units.Theatomsbondedtoeachothercovalently
formsthe backboneofthepolymer.Examples: Polyethylene, PVC,polystyrene, polyamides,etc.
c)Cross-linked polymers:Cross-linked polymers are polymers in which monomer units are cross-linked
together to form a three-dimensional network polymer. Examples: polyester fiberglass, polyurethanes
used as coatings, adhesives, vulcanized rubber, etc.
b)Branchedpolymer: Abranchedpolymerisamacromoleculemadefromthepolymerizationof
monomersand hasabranchedstructure.Thepropertiesofthese polymersaremainlyaffectedby
the amountofbranching.Examples:low-densitypolyethylene(LDPE), high- densitypolyethylene
(HDPE),and polypropylene(PP).
Linear polymer Branched polymer Cross-lined polymerNPTEL
ii.Amorphous and crystalline polymer
a)Amorphouspolymers:
•Amorphous pol
ymersarepolymers thathavenocrystallineregions and no uniformlypacked molecules.
•Instead,a
apolymerhaverandomlypacked moleculeswith nosharpmelting point.
•Examples:P
olymethyl methacrylate (PMMA/Acrylic),polystyrene(PS),polycarbonate (PC), polysulfone(PSU),
polyvinylchloride (PVC),acrylonitrilebutadiene styrene(ABS)and polyetherimide (PEI), etc.
b)Crystalline
polymers:
•Crystallinepol
ymersarepolymers thathavea well-organized structure.
•Theyar
definedbytheirstrictcomposition and perfect order ortranslationof atoms or
molecules.
•A p
the shape of thelatticedefiningeach crystaltype.
•Examples: P
olyethylene,polypropylene,polyesters,nylons, etc.NPTEL
a)Amorphouspolymers:
•Amorphous pol
ymersarepolymers thathavenocrystallineregions and no uniformlypacked molecules.
•Instead,a
apolymerhaverandomlypacked moleculeswith nosharpmelting point.
•Examples:P
olymethyl methacrylate (PMMA/Acrylic),polystyrene(PS),polycarbonate (PC), polysulfone(PSU),
polyvinylchloride (PVC),acrylonitrilebutadiene styrene(ABS)and polyetherimide (PEI), etc.
b)Crystalline
polymers:
•Crystallinepol
ymersarepolymers thathavea well-organized structure.
•Theyar
definedbytheirstrictcomposition and perfect order ortranslationof atoms or
molecules.
•A p
the shape of thelatticedefiningeach crystaltype.
•Examples: P
olyethylene,polypropylene,polyesters,nylons, etc.NPTEL
iii.Homopolymer and Copolymer
a)Homopolymer:Po lymerscomposed of only one repeating unitinthe polymer moleculesare
known as homopolymers.
b)Copolymer:Po
lymerscomposed oftwodifferent repeating unitsinthe polymer moleculearedefined as copolymers.
There areseveral types of copolymers. Theyare:
▪Random c :Therepeating unitsarearranged randomly on the chain molecule.
▪Blockc
:Thechain consists of relatively long sequences (blocks) of each
repeating unit chemically bound together.
▪Graftc
:Sequences of one monomer (repeating unit)
are“grafted” onto a backbone of the other monomer type.
▪Alternating copolymer:Thereisan ordered (alternating) arrangement of thetwo
repeating units along the polymer chain.NPTEL
a)Homopolymer:Po lymerscomposed of only one repeating unitinthe polymer moleculesare
known as homopolymers.
b)Copolymer:Po
lymerscomposed oftwodifferent repeating unitsinthe polymer moleculearedefined as copolymers.
There areseveral types of copolymers. Theyare:
▪Random c :Therepeating unitsarearranged randomly on the chain molecule.
▪Blockc
:Thechain consists of relatively long sequences (blocks) of each
repeating unit chemically bound together.
▪Graftc
:Sequences of one monomer (repeating unit)
are“grafted” onto a backbone of the other monomer type.
▪Alternating copolymer:Thereisan ordered (alternating) arrangement of thetwo
repeating units along the polymer chain.NPTEL
3. Classification based on the force of attraction
•To form bonds, atoms employ valence electrons. Consequently, the type of bond formed depends on the electronic configuration
of the atom
s.
•Depending on the extent of electron involvement, chemical bonds may be classified as either primary or secondary.
•Primary bonds are of three types: io
nic, metallic, and covalent. The atoms in a polymer are mostly bonded by covalent bonds.
•The forces of attraction responsible for the cohesive aggregation between individual molecules are referred to as s
econdary
valence forces such as van der Waals, hydrogen, and dipole bonds.Chemical bonds
Primary
Secondary
Ionic
Covalent
van der Waals
Hydrogen
Dipole bonds
MetallicNPTEL
•To form bonds, atoms employ valence electrons. Consequently, the type of bond formed depends on the electronic configuration
of the atom
s.
•Depending on the extent of electron involvement, chemical bonds may be classified as either primary or secondary.
•Primary bonds are of three types: io
nic, metallic, and covalent. The atoms in a polymer are mostly bonded by covalent bonds.
•The forces of attraction responsible for the cohesive aggregation between individual molecules are referred to as s
econdary
valence forces such as van der Waals, hydrogen, and dipole bonds.Chemical bonds
Primary
Secondary
Ionic
Covalent
van der Waals
Hydrogen
Dipole bonds
MetallicNPTEL
Based on the force of attractions polymers can be generally classified as fibers, plastics, or elastomers.
i.Fibers
•Fibers are linear polymers with high symmetry and high intermolecular forces.
•They are characterized by high modulus, high tensile strength, and moderate extensibilities.
•They are used in a variety of industries such as aerospace, automotive, marine, and construction.
•Examples: nylon- 6
,6, rayon Lyocell, modal diacetate fiber, triacetate fiber, etc.
ii.Elastomers
•Molecules of elastomers have irregular structure, weak intermolecular attractive forces, and very flexible polymer chains
•Chain segments of elastomers can undergo high local mobility.
•Consequently, elastomers exhibit high extensibility (up to 1000%) from which they recover rapidly on the removal of the
im
posed stress.
•Examples: Natural rubber, polyurethane, polybutadiene, neoprene and silicone.
iii.Plastics
•Plastics fall between the structural extremes represented by fibers and elastomers.
•Examples: Polyethylene, polypropylene, polyvinyl chloride (PVC), polystyrene, and pol
yethylene terephthalate (PET).NPTEL
i.Fibers
•Fibers are linear polymers with high symmetry and high intermolecular forces.
•They are characterized by high modulus, high tensile strength, and moderate extensibilities.
•They are used in a variety of industries such as aerospace, automotive, marine, and construction.
•Examples: nylon- 6
,6, rayon Lyocell, modal diacetate fiber, triacetate fiber, etc.
ii.Elastomers
•Molecules of elastomers have irregular structure, weak intermolecular attractive forces, and very flexible polymer chains
•Chain segments of elastomers can undergo high local mobility.
•Consequently, elastomers exhibit high extensibility (up to 1000%) from which they recover rapidly on the removal of the
im
posed stress.
•Examples: Natural rubber, polyurethane, polybutadiene, neoprene and silicone.
iii.Plastics
•Plastics fall between the structural extremes represented by fibers and elastomers.
•Examples: Polyethylene, polypropylene, polyvinyl chloride (PVC), polystyrene, and pol
yethylene terephthalate (PET).NPTEL
Applications of fibers, elastomer and plastic polymers
Fibres
✔Textiles
✔Carpets and ropes
✔Seat covers and dashboards
✔Insulation and roofing
Elastomers
✔Gloves
✔Seals
✔Gaskets
✔Swimming suits
Plastics
✔Packaging
✔Automotive parts
✔Toys
✔Medical devices
Swimming suitsNPTEL
Fibres
✔Textiles
✔Carpets and ropes
✔Seat covers and dashboards
✔Insulation and roofing
Elastomers
✔Gloves
✔Seals
✔Gaskets
✔Swimming suits
Plastics
✔Packaging
✔Automotive parts
✔Toys
✔Medical devices
Swimming suitsNPTEL
4. Classification based on the polymerization mechanism
Depending on the type of polymerization reaction involved in their formation polymers may be classified broadly as condensation,
addition, or ring-opening polymers.
i.Condensation polymers•Condensation polymers are formed from a series of condensation reactions type, in which any two species (monomers, dimers, tri mers,
etc.) can react at any time leading to a larger molecule where a small molecule, usually water or ammonia, is eliminated.
•Examples: polyamides (e.g., nylon 6,6), polyesters (e.g., poly(ethylene terephthalate), urea- fo
rmaldehyde, etc.
ii.Addition polymers
•Addition polymers are produced by reactions in which monomers are added one after another to a rapidly growing chain.
•The three fundamental steps are involved in polymerization are initiation, propagation, and termination.
•Monomers generally employed in addition polymerization are unsaturated (usually with carbon-c
arbon double bonds).
•Examples: polystyrene, polyethylene, polyacrylonitrile, poly vinyl chloride, etc.
ii.
Ring-opening polymers
•They are derived from the cleavage and then polymerization of cyclic compounds.
(CH
2)
5NH
C
O
(CH
2)
5N C
H O
nNPTEL
Depending on the type of polymerization reaction involved in their formation polymers may be classified broadly as condensation,
addition, or ring-opening polymers.
i.Condensation polymers•Condensation polymers are formed from a series of condensation reactions type, in which any two species (monomers, dimers, tri mers,
etc.) can react at any time leading to a larger molecule where a small molecule, usually water or ammonia, is eliminated.
•Examples: polyamides (e.g., nylon 6,6), polyesters (e.g., poly(ethylene terephthalate), urea- fo
rmaldehyde, etc.
ii.Addition polymers
•Addition polymers are produced by reactions in which monomers are added one after another to a rapidly growing chain.
•The three fundamental steps are involved in polymerization are initiation, propagation, and termination.
•Monomers generally employed in addition polymerization are unsaturated (usually with carbon-c
arbon double bonds).
•Examples: polystyrene, polyethylene, polyacrylonitrile, poly vinyl chloride, etc.
ii.
Ring-opening polymers
•They are derived from the cleavage and then polymerization of cyclic compounds.
(CH
2)
5NH
C
O
(CH
2)
5N C
H O
nNPTEL
1.Thermoplastics
•Soften a flowunder the actionofheat andpressure.Upon cooling, thepolymerhardens andassumesthe shapeof
the mould (container).
•Thermoplastics,w
hencompounded with appropriate ingredients,canusually withstandseveralofthese heatingand
coolingcycleswithout suffering any structural breakdown.
•Examplesof the
rmoplastic polymersare polyethylene,polystyrene, and nylon.
•Thermosets us
uallyexist initially asliquidscalledprepolymers;theycanbeshapedinto
desiredformsbytheapplicationofheatand pressure,butareincapableofundergoing
repeated cyclesof softening and hardening.
•Exampleso
fthermosettingpolymersinclude urea–formaldehyde, phenol–formaldehyde,
andepoxies.
2.Thermosets
•Athe is apolymer that, when heated, undergoesa chemicalchange to producea cross-linked, solidpolymer.
5. Classification based on thermal properties: On the basis of thermal response polymers can be classified as thermoplastics
and thermosets.NPTEL
•Soften a flowunder the actionofheat andpressure.Upon cooling, thepolymerhardens andassumesthe shapeof
the mould (container).
•Thermoplastics,w
hencompounded with appropriate ingredients,canusually withstandseveralofthese heatingand
coolingcycleswithout suffering any structural breakdown.
•Examplesof the
rmoplastic polymersare polyethylene,polystyrene, and nylon.
•Thermosets us
uallyexist initially asliquidscalledprepolymers;theycanbeshapedinto
desiredformsbytheapplicationofheatand pressure,butareincapableofundergoing
repeated cyclesof softening and hardening.
•Exampleso
fthermosettingpolymersinclude urea–formaldehyde, phenol–formaldehyde,
andepoxies.
2.Thermosets
•Athe is apolymer that, when heated, undergoesa chemicalchange to producea cross-linked, solidpolymer.
5. Classification based on thermal properties: On the basis of thermal response polymers can be classified as thermoplastics
and thermosets.NPTEL
Applications of thermoplastic and thermoset polymers
Thermoplastic
✔Aircraft cabins
✔Medical devices
✔Pipe systems
Thermoset
✔Cell tower tops
✔Heat shields
✔Circuit breakers
✔Disc brake pistons
✔Agricultural feeding troughs Aircraft cabin
Disc brake Circuit breaker Heat shieldNPTEL
Thermoplastic
✔Aircraft cabins
✔Medical devices
✔Pipe systems
Thermoset
✔Cell tower tops
✔Heat shields
✔Circuit breakers
✔Disc brake pistons
✔Agricultural feeding troughs Aircraft cabin
Disc brake Circuit breaker Heat shieldNPTEL
Let us now discuss them in a bit detail !
Therearetwotypesofpolymerizationreactions:
1.Step-
growthpolymerization
2.Chain-
growthpolymerizationNPTEL
Therearetwotypesofpolymerizationreactions:
1.Step-
growthpolymerization
2.Chain-
growthpolymerizationNPTEL
2. Chain- growth polymerization: Chain- growth polymerization is a polymerization technique where unsaturated
monomer molecules add onto the active site on a growing polymer chain one at a time.
Step 1: Step 2: Step 3:
1.Step-g Step-growth polymerization refers to a type of polymerization mechanism in which
bi-functional or multifunctional monomers react to form first dimers, then trimers, longer oligomers and eventually long
chain polymers.
Step 1:
Initiator
Monomer
Step 2:
Initiator
Monomer
•Thus, the rate of growth of the polymer chain is very different in these two cases.
•For step-g
logarithmic
and for the chain-growth, the growth is linear.
The molecular size of a polymer can quantitatively estimate by the degree of polymerization (DP).
Step 3:
Initiator
MonomerNPTEL
monomer molecules add onto the active site on a growing polymer chain one at a time.
Step 1: Step 2: Step 3:
1.Step-g Step-growth polymerization refers to a type of polymerization mechanism in which
bi-functional or multifunctional monomers react to form first dimers, then trimers, longer oligomers and eventually long
chain polymers.
Step 1:
Initiator
Monomer
Step 2:
Initiator
Monomer
•Thus, the rate of growth of the polymer chain is very different in these two cases.
•For step-g
logarithmic
and for the chain-growth, the growth is linear.
The molecular size of a polymer can quantitatively estimate by the degree of polymerization (DP).
Step 3:
Initiator
MonomerNPTEL
Consider the formula for polystyrene:
-CH
2-CH-
n
The subscript designation, n, in the equations indicates the number of repeating units present in the polymer chain
(molecule). This is known as the degree of polymerization (DP) .It specifies the length of polymer molecule.
❖Polymerization proceeds by the reaction of monomers to form a dimer, which in turn reacts with another monomer to for
m a trimer and so on.
❖Reaction may also be between dimers, trimers, or any molecular species within the reaction mixture to form a p
rogressively larger molecule.
❖In either case, a series of linkages is built between the repeating units, and the resulting polymer molecule,
o
ften called a polymer chain.
❖Low-m
weight polymerization products such as dimers, trimers, tetramers, etc.,
are referred to as oligomers .
“A high degree of polymerization is normally required for a material to develop useful
properties so that it can be appropriately described as a polymer”.
Degree of polymerizationNPTEL
-CH
2-CH-
n
The subscript designation, n, in the equations indicates the number of repeating units present in the polymer chain
(molecule). This is known as the degree of polymerization (DP) .It specifies the length of polymer molecule.
❖Polymerization proceeds by the reaction of monomers to form a dimer, which in turn reacts with another monomer to for
m a trimer and so on.
❖Reaction may also be between dimers, trimers, or any molecular species within the reaction mixture to form a p
rogressively larger molecule.
❖In either case, a series of linkages is built between the repeating units, and the resulting polymer molecule,
o
ften called a polymer chain.
❖Low-m
weight polymerization products such as dimers, trimers, tetramers, etc.,
are referred to as oligomers .
“A high degree of polymerization is normally required for a material to develop useful
properties so that it can be appropriately described as a polymer”.
Degree of polymerizationNPTEL
Degree of polymerization
Thedegreeof polymerization can quantitatively estimatethemolecular sizeofapolymer.Thiscanalsobe done byuse of the term
molecularweight(MW).Bydefinition,MWof the polymer=Degreeofpolymerization×Molecularweight of therepeatingunit.
Apolymer sampleis actuallycomposed ofmillionsofpolymer molecules having different chainlengths.Thismeansthatadistribution of
molecularweightexists forsynthetic polymers. A typical molecular weightdistributioncurveforapolymerisshown below.NPTEL
Thedegreeof polymerization can quantitatively estimatethemolecular sizeofapolymer.Thiscanalsobe done byuse of the term
molecularweight(MW).Bydefinition,MWof the polymer=Degreeofpolymerization×Molecularweight of therepeatingunit.
Apolymer sampleis actuallycomposed ofmillionsofpolymer molecules having different chainlengths.Thismeansthatadistribution of
molecularweightexists forsynthetic polymers. A typical molecular weightdistributioncurveforapolymerisshown below.NPTEL
Amount of polymer
Molecular weightNPTEL
Molecular weightNPTEL
❑A pol isa largemolecule(macromolecule)builtupbythe repetition ofsmall chemical
units.
❑Polymerizationi
sa process ofreactingmonomermoleculestogetherinachemicalreaction
toform polymer chains or three-dimensionalnetworks.
❑Therear
twotypesof polymerization reactions:Step-growthpolymerizationChain-growth
polymerization
❑Polymersca
nbeclassifiedbasedon theoriginofthe polymer, polymerstructure,
polymerizationmechanism,preparative techniques, or thermal behaviour.
❑Polymers have a wide verity of applications raging from regular house
hol
d applications to aircraft cabin material.NPTEL
units.
❑Polymerizationi
sa process ofreactingmonomermoleculestogetherinachemicalreaction
toform polymer chains or three-dimensionalnetworks.
❑Therear
twotypesof polymerization reactions:Step-growthpolymerizationChain-growth
polymerization
❑Polymersca
nbeclassifiedbasedon theoriginofthe polymer, polymerstructure,
polymerizationmechanism,preparative techniques, or thermal behaviour.
❑Polymers have a wide verity of applications raging from regular house
hol
d applications to aircraft cabin material.NPTEL
⮚Textbook of Polymer Science by Billmeyer.
⮚Polymer Science and Technology by Joel R. Fried.
⮚Polymer Science by Vasant R. Gowariker, N. V. Viswanathan,
Jayadev SreedharNPTEL
⮚Polymer Science and Technology by Joel R. Fried.
⮚Polymer Science by Vasant R. Gowariker, N. V. Viswanathan,
Jayadev SreedharNPTEL
Thank you…NPTEL
Physics of Functional Materials & Devices
Prof. Amreesh Chandra
Department of Physics, IIT KHARAGPUR
Module 01: Introduction to Functional Materials
Lecture 05 : Introduction to nanomaterialsNPTEL
Prof. Amreesh Chandra
Department of Physics, IIT KHARAGPUR
Module 01: Introduction to Functional Materials
Lecture 05 : Introduction to nanomaterialsNPTEL
⮚Definition of nanomaterials
⮚Why properties change at nanoscale?
⮚Classification of nanomaterialsNPTEL
⮚Why properties change at nanoscale?
⮚Classification of nanomaterialsNPTEL
Nano -a billionth –(1 x 10
-9
)
The term is ‘nanotechnology’ is new but the concept and structures have been known to
mankind for many-many-many centuries!
History has been full of examples dealing with the use of nano-Au/ Ag or other elements for
medicinal applications.
Exact time, when humans started using the advantage, is not actually clear
but it was known to them is clear!NPTEL
-9
)
The term is ‘nanotechnology’ is new but the concept and structures have been known to
mankind for many-many-many centuries!
History has been full of examples dealing with the use of nano-Au/ Ag or other elements for
medicinal applications.
Exact time, when humans started using the advantage, is not actually clear
but it was known to them is clear!NPTEL
If we concentrate on more recent times, then in 1857, Michael Faraday published his results to
explain the way metal particles affect the colours of church glasses.
This was explained in 1908 by Gustav Mie.
But, Richard Feynman is considered as the ‘Father’ of modern day Nanotechnology.
In 1960, he delivered a lecture, in a meeting of APS, with title: “There is Plenty of
Room at the Bottom”, where he indicated that the ‘novel’ physics, which can evolve
if nanosized materials were investigated carefully.
In 1957, Ralph Landauer, working in IBM, using his vast knowledge in
theoretical physics, suggested the importance of quantum mechanical
effects in explaining the properties at ‘nanoscale’ and ‘nanomaterials’.NPTEL
explain the way metal particles affect the colours of church glasses.
This was explained in 1908 by Gustav Mie.
But, Richard Feynman is considered as the ‘Father’ of modern day Nanotechnology.
In 1960, he delivered a lecture, in a meeting of APS, with title: “There is Plenty of
Room at the Bottom”, where he indicated that the ‘novel’ physics, which can evolve
if nanosized materials were investigated carefully.
In 1957, Ralph Landauer, working in IBM, using his vast knowledge in
theoretical physics, suggested the importance of quantum mechanical
effects in explaining the properties at ‘nanoscale’ and ‘nanomaterials’.NPTEL
...work continued...newer and newer phenomenon were being observed…
The field was becoming too chaotic and with too much of confusion.
So, in 1996, many government agencies and research councils came together to
assess the trend, status, development and related aspects.
That is when the use of the term
‘nanotechnology’ or
‘nanomaterials’
started getting some specific
definitions.NPTEL
The field was becoming too chaotic and with too much of confusion.
So, in 1996, many government agencies and research councils came together to
assess the trend, status, development and related aspects.
That is when the use of the term
‘nanotechnology’ or
‘nanomaterials’
started getting some specific
definitions.NPTEL
Nanomaterial
Specialclassofmaterials,whichhaveatleast
one ofthedimensions inthe range 1-100
nm.NPTEL
Specialclassofmaterials,whichhaveatleast
one ofthedimensions inthe range 1-100
nm.NPTEL
Confinement in NANOSTRUCTURESNPTEL
BULK
WELL WIRE DOT
Nano Size Spatial confinement (Carriers)NPTEL
WELL WIRE DOT
Nano Size Spatial confinement (Carriers)NPTEL
Examples of 0- D Nanomaterials
Ref: doi.org/10.1088/1361-6528/ab084c, 10.1016/j.pmatsci.2011.08.003, 10.1039/C3NR03511ENPTEL
Ref: doi.org/10.1088/1361-6528/ab084c, 10.1016/j.pmatsci.2011.08.003, 10.1039/C3NR03511ENPTEL
Examples of 1- D Nanomaterials
Ref: 10.1016/j.energy.2017.02.018, 10.1039/C8TA00945G, 10.1016/j.electacta.2016.09.033NPTEL
Ref: 10.1016/j.energy.2017.02.018, 10.1039/C8TA00945G, 10.1016/j.electacta.2016.09.033NPTEL
Examples of 2- D Nanomaterials
Nanodisks
Nanosheets Nanosheets
Nanowalls
NanoplatesNPTEL
Nanodisks
Nanosheets Nanosheets
Nanowalls
NanoplatesNPTEL
Nanostructured Materials
0 D
Quantum Dots
1 D
Quantum Wires
2 D
Quantum WellsNPTEL
0 D
Quantum Dots
1 D
Quantum Wires
2 D
Quantum WellsNPTEL
Surface area
Nano Materials have a relatively larger surface area when compared to the same
volume or mass of the material produced in a larger form.
Sphere of radius “r”.
❑Surface Area =4πr
2
.
❑Volume= 4/3πr
3
❑S/V Ratio= 3/r.
Thus when the radius of the sphere decreases, its
Surface to Volume ratio increases NPTEL
Nano Materials have a relatively larger surface area when compared to the same
volume or mass of the material produced in a larger form.
Sphere of radius “r”.
❑Surface Area =4πr
2
.
❑Volume= 4/3πr
3
❑S/V Ratio= 3/r.
Thus when the radius of the sphere decreases, its
Surface to Volume ratio increases NPTEL
Number of electrons and Density of statesNPTEL
Quantum dot
Quantum wire
Bulk material
Quantum well
The number of conduction electrons
with a particular energy depends on
the value of the energy and also on
the dimensionality of the space.
In 1 D –Fermi region containing
electrons has the length 2k
F, 2D –πk
F
2
and 3 D -4πk
F
3/3
We know, D(E) denote the density of
states as a function of energy =
dN/dE ????????????meaning: number of
electrons dN with an energy E within
a narrow range of energy dE=E
2-E
1
Fig. N(E) and D(E) as function of E for four quantum structures in
the square well Fermi- gas approximation.NPTEL
Quantum wire
Bulk material
Quantum well
The number of conduction electrons
with a particular energy depends on
the value of the energy and also on
the dimensionality of the space.
In 1 D –Fermi region containing
electrons has the length 2k
F, 2D –πk
F
2
and 3 D -4πk
F
3/3
We know, D(E) denote the density of
states as a function of energy =
dN/dE ????????????meaning: number of
electrons dN with an energy E within
a narrow range of energy dE=E
2-E
1
Fig. N(E) and D(E) as function of E for four quantum structures in
the square well Fermi- gas approximation.NPTEL
Additional advantages of nanomaterials
•Enhanced surface-to- volume ratio
•Reduced transport lengths for both mass and charge transport
•High surface area
•Low density
•Low mass requirement
•Reduction in costsNPTEL
•Enhanced surface-to- volume ratio
•Reduced transport lengths for both mass and charge transport
•High surface area
•Low density
•Low mass requirement
•Reduction in costsNPTEL
Application of nanomaterials
Applications
Energy Medical Electronic Optical
Supercapacito
rs
Batterie
s
Solar
cells
Fuel
cells
Wind
turbines
Optical sensors
Imagin
g
Optoelectroni
cs
Non-
linearity
Photonic
s
Medicine s
Drug delivery
Memory chips
Touch screen layers
Electronic gadgetsNPTEL
Applications
Energy Medical Electronic Optical
Supercapacito
rs
Batterie
s
Solar
cells
Fuel
cells
Wind
turbines
Optical sensors
Imagin
g
Optoelectroni
cs
Non-
linearity
Photonic
s
Medicine s
Drug delivery
Memory chips
Touch screen layers
Electronic gadgetsNPTEL
⮚Definition of nanomaterials was discussed.
⮚The vast range of applications of these materials were also presented.
⮚The discussion has been kept brief and deals with only those points, which are relevant to
this course.
⮚The field of nanotechnology is rapidly evolving!NPTEL
⮚The vast range of applications of these materials were also presented.
⮚The discussion has been kept brief and deals with only those points, which are relevant to
this course.
⮚The field of nanotechnology is rapidly evolving!NPTEL
⮚Introduction toN anotechnology, CharlesP.Poole, Jr.andFrankJ.Owens,wiley-
interscience.
⮚AT
ofNanoscience andNanotechnology,P. I.Varghese and Thalappil,McGraw
HillEducation,2017.NPTEL
interscience.
⮚AT
ofNanoscience andNanotechnology,P. I.Varghese and Thalappil,McGraw
HillEducation,2017.NPTEL
Thank you…NPTEL
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