The document outlines Dr. R.K. Khandal's presentation on nanocomposites for optical plastics. It discusses various optical applications that currently use glass and the potential for plastics. It describes different types of nanocomposites for optical applications including metal-glass and metal-polymer composites. Work done at Shriram Institute includes developing acrylate-based nanocomposites with improved refractive index and properties by dispersing metal salts and using co-monomers. Gamma radiation was used for polymerization. The nanocomposites showed enhanced optical and mechanical properties suitable for applications like lenses.

1. DR. R.K. KHANDAL
DIRECTOR
NANOCOMPOSITES FOR
OPTICAL PLASTIC
MATERIALS
SHRIRAM INSTITUTE FOR INDUSTRIAL RESEARCH
19, UNIVERSITY ROAD, DELHI - 110007

2. OUTLINE OF
PRESENTATION
OPTICAL APPLICATIONS
OPTICAL PLASTICS
NANO COMPOSITES
METAL CONTAINING PLASTICS
FUTURE OF NANO TECHNOLOGY
 An overview presenting, past, present and future
options in novel materials

3. OPTICAL APPLICATIONS
BIOMEDICALS ENGINEERING INSTRUMENTATION INFRA STRUCTURE
OPHTHALMIC
LENSES
AUTOMOTIVE
AVIATION
SPACE
RADIATION
SHIELDING
TELESCOPE
BINOCCULAR
CAMERA
SENSORS
OPTICS
COMMUNICATION
(Fibre Optics)
SIGNALS
(Railways, Aviation,
Road, transport etc.)
SHIELDING
 Glass is the most conventional material used in all the
above applications; Plastics are viable alternatives
SPECTCLE
CONTACT
INTRAOCULAR

4. BIO-MEDICAL APPLICATIONS
Optical Devices Parameters Materials Used
Spectacle lenses Refractive index, optical Glass, Polythiourethanes
clarity, Abbe number, Polyacrylates, Polycarbonates
Sun glasses Refractive index, UV- Glass, Polyacrylates
resistance, aesthetics
Contact lenses Refractive index, clarity, Polyacrylates and modified
biocompatibility, softness/ acrylates, silicones and
rigidity modified silicones
Intraocular lenses Refractive index, Polyacrylates and modified
transparency acrylates and silicones
biocompatibility,
 Glass has been completely replaced by plastics
 Development of newer plastics is the key

5. INSTRUMENTAL APPLICATIONS
Optical Device Parameters Materials Used
Binocular lenses Magnifying power, Glass, Polyacrylates,
Refractive index, clarity Polycarbonates
Telescopes lenses Magnifying power, Glass, Polyacrylates,
Refractive index, clarity Polycarbonates
Magnifying glass Magnifying power, Glass, Polyacrylates,
Refractive index, clarity Polycarbonates
 Tailoring of available materials for achieving
varying refractive index Plastics
 Plastics provide flexibility and options

6. INFRASTRUCUTRE APPLICATIONS
Optical Device Parameters Materials Used
Optical waveguides Refractive index, Lithium niobate (LiNbO3),
absorbance / Potassium titanyl
transmittance phosphate (KTiOPO4)
in polyacrylate
Optical fibres Refractive index, Glass, Polyacrylates
rate of light Metals
transmission
 Research is going on for alternate plastic materials
for the above applications
 Conventional materials would not have been
adequate to meets the demand

7. ENGINEERING APPLICATIONS
Optical Device Parameters Materials Used
Optical modulators Refractive index, Lithium niobate (LiNbO3),
total internal reflection, Potassium titanyl phosphate
infrared absorbance (KTiOPO4)
Optical demodulators Refractive index, Lithium niobate (LiNbO3),
total internal reflection, Potassium titanyl phosphate
infrared absorbance (KTiOPO4)
Optical interconnectors Refractive index, Lithium niobate (LiNbO3),
total internal reflection, Potassium titanyl phosphate
infrared absorbance (KTiOPO4)
Liquid crystal dislays Refractive index, Glass, Polyacrylates
(LCD) absorbance / transmittance
 Use of plastic materials leads to the development of
effective, less cumbersome technology

8. GLOBAL STATUS : PLASTIC LENSES
CHARACTERISTICS
800-850 million lenses per year
∈ 7-8 billion in sales
Lens replacement frequency : 2-3 years
 Indian requirement is met by imports only

9. 10%
17%
33%
45%
55%
98%
0%
20%
40%
60%
80%
100%
120%
Latin America United States Canada Western Europe Asia Pacific Japan
Countries
%asshareoftotallenses
MARKET FOR ANTI-REFLECTING LENSES

10. Lens market breakdown by material
Plastic lenses,
medium, high
indexes
(>1.5 index)
22%
Plastic lenses
<1.5 index
42%
Glass lenses
36%
MATERIALS USED : LENSES
 Clear picture of the gaining popularity for optical plastics
 Major plastics is polycarbonate

11. INDIAN STATUS : LENSES
140 million pieces per year
Export = 112 million pieces per year
Domestic = 28 million pieces per year
 Complete requirement is met by imports
 Indigenous technologies are required for increase
in Indian market demand
 Optical plastic industry is engaged in job work

12. DESIGN CRITERIA FOR
OPTICAL PLASTICS
Evaluation of the environment in which the plastic
is to be used
Physical and optical properties of the plastics
Physical properties to be considered are density,
hardness, rigidity
Service temperature, thermal expansion, electrical
and thermal conductivity

13. CLASSIFICATION OF OPTICAL MATERIALS
Gradient index materials : Glass & Polyacrylates
Low Refractive Index : < 1.5 (CR 39, PMMA & Crown glass)
Medium Refractive Index : 1.5-1.6 (Polycarbonates)
High Refractive Index : > 1.6 (Polythiourethane)
Infrared refractive materials : Fused silica and polycarbonates
Ultra-violet refractive index : Fused silica, polycarbonates
materials and Glass
 Materials used are fused silica, polycarbonates and
glass

14. OPTICAL PLASTICS
PAST
Material : Polymethyl methacrylate (PMMA)
Applications : Spectacle lenses, Contact lenses,
Camera lenses, Binocular lenses
Features : High rigidity leading to eye-discomfort in
internal wear such as contact lenses.
Poor aesthetics leading to bulge eye look.
Poor shatter resistance leading to delicate
handling
 Availability of the right type of materials was a
constraint

15. PRESENT
Material : Modified acrylates and silicones,
Thiourethanes, polycarbonatyes
Applications :  Flexible intraocular lenses,
 Extended wear contact lenses
 Contact lenses of variable wear
Features :  Fixed optical properties
 Easy to use
 Economic
 Better customer appeal
OPTICAL PLASTICS
 With newer materials, novel applications have
become possible

16. FUTURE
Material : Organic/ Inorganic hybrid materials,
Polymer composites
Applications : Lenses, Optical waveguides,
Optical fillers, Optical
transmitters
Features : Wide range of refractive index,
Improved stability and hardness,
Tailor-making of optical properties
possible
OPTICAL PLASTICS
 Nano composites have a great potential for future

17. Advantages Disadvantages
Light weight Soft surface
Impact resistance Limitation of refractive index
Good machineability Ultra high & low refractive index
not possible
Good aesthetics
Good processability
 All the above disadvantages can be overcome by
only nanocomposites
OPTICAL PLASTICS
 Nanocomposites can be designed

18. NANO MATERIALS : CROSS-SECTIONAL AND
INTERDISCIPLINARY APPROACH
Automotive
Components
Paper
Cosmetics
Textiles
Displays
Coatings
Emulsions
Dispersions
Plastics
Films
Powders
Science
Chemistry
Physics
Analytics
Material
Science
Biology
Applications End
Products
Materials/
Intermediates
Nano-
materials
 Developing Nanomaterials is a challenge !

19. TYPES OF NANO-
COMPOSITES FOR OPTICAL
APPLICATIONS
METAL-GLASS COMPOSITES
METAL-POLYMER COMPOSITES
 Areas of application include sensors, wave guides,
optical fibres, etc.
 Complementary and synergistic compositions for
extraordinary effect

20. TYPES OF NANOCOMPOSITES
FOR OPTICAL APPLICATIONS
METAL-GLASS COMPOSITES
Incorporation of metal nanoparticles (Ag, Au) in glass
leading to colored glass
Good absorption of incident light: negligible scattering
Concept used since 15th century
 Colloidal dispersions of metals in inorganics was
an established way

21. METAL-POLYMER COMPOSITES
Transparency is achieved
Substantial reduction in intensity loss which is size
dependent
Refractive index above 2.5 (ultra-high) and refractive
index below 1.25 (ultra-low) is possible only with
nanocomposites
TYPES OF NANOCOMPOSITES
FOR OPTICAL APPLICATIONS
 A novel idea of imparting advantageous features of
metals to plastics for better

22. METAL CONTAINING GLASS
Chronology Materials
Potable gold, Potable silver
Prepn. of colored glass by the
incorporation of purple, violet, brown or
black colloidal powders
Use of colloidal gold powders for the
painting of enamel
Detailed analysis of color of gold colloids
Formation of ruby glass using gold
particles
Coloured glass with unique features
15th
Century
16th
Century
17th
Century
18th
Century
19th
Century
20th
Century

23. PRESENT
Materials : Preparation of dichroic films of
gelatin and Os, Rh, Ag, Au, P, Hg, As, S,
etc. Dichroic films of PVA-Au, Ag & Hg
Silver add crystallites in ramie, hemp,
bamboo, silk, wool, viscose, (5-14nm)
Applications : Eye-wear lenses, cameras, binoculars,
sensors, solar applications, filters,
transmitters, wave guides, reflectors, etc.
METAL CONTAINING POLYMERS
 Metal containing polymers are a novel idea !

24. FUTURE OF METAL-CONTAINING
POLYMERS
NANOPARTICLE
Electronics
Multiuse
Chemical Industries
Defence
OpticsConsumers
Medical/Biology
Solar Cells
Sensors
Electrocatalysis
Photocatalysis
 For any application, nanotechnology is a blend of the science of physics,
chemistry and biology
 Field of optics has seen a lot success with nanotechnology; coatings and
diagnostics

25. As the scale goes down, the activity rises mainly due to the lowering distances at which the
interparticle interactions occur leading to evolution of energy.
Emulsion
High surface energy,
Non-homogeneous, unstable
Thermodynamically
Extremely
High
Irreversible
System Scale Activity Remarks
Mixtures >micrometer Low
Suspension
Dispersion
micrometer Medium kinetically stable
unstable
Microemulsion
Solubilised
nanometer Moderately
High stability probable
Thermodynamic
Macromolecular angstrom High
Molecular
Atomic
Very High
Nuclear
Spontaneous
atomic
sub-atomic
Thermodynamically stable
Basis for new materials
Source of energy
SIZE - DEPENDENT PROPERTIES
OF MATERIALS

26. CHANGE OF PROPERTIES AT
THE NANOMETER SCALE
Chemical reactivity
Electronic properties
Optical properties (absorption, scattering)
Mechanical properties (hardness)
Transport properties (heat, current)
Bioavailability
In addition to quantum effects, the increased
surface-volume ratio at the nanometer scale bring
improvements in ;
 Nanomaterials have extraordinary features

27. INCREASE IN SURFACE AREA
(at constant volume fraction)
1 µm 100 nm 10 nm
o. of particles 1 10
3
10
6
face Area
unit volume
1X 10X 100X
Decreasing Particle Size

28.  Combination of two or more phases where at
least one phase is in nanometer range
TYPICAL MORPHOLOGIES

29. FEATURES OF NANOCOMPOSITES FOR
OPTICAL APPLICATIONS
 Particle size less than 50-100nm leads to less scattering of
light and therefore improves transparency
 By incorporation of inorganic colloids with extreme
refractive index in organic polymers ultra high refractive
is possible
 High surface to volume ratio improves reduces scattering
losses
 Drawbacks of plastics can be eliminated
 Tailor-making of refractive index possible

30. WORK CARRIED OUT AT SRI
 Selection of suitable metal salts for dispersion
 Ba(OH)2, BaSO4, Ba(NO3)2, BaCl2,
 PbO, (CH3COO)2Pb, PbNO3,
 LaCl3, La2O3, La(NO3)3,
 TiO2
 Nb2O3, NbC
 Acrylic acid as monomer
 Selection of polymerization technique Thermal, Gamma Selection of
suitable initiator for thermal polymerization Benzoyl peroxide, Azo
bis-isobutyronitile (AIBN)
 Selection of suitable dose for polymerization by Gamma radiation
 Casting of lenses
 Eight patents on the product & process

31.  Characterization of cast lenses for various opto-
mechanical properties
 Colour
 Refractive index
 Abbe number
 Shore-D hardness
 Scratch resistance
 Haze
 Pencil hardness
 Impact resistance
 Machinability
 Heat distortion (°
C)
 Specific gravity
 Transmittance (%)
 Yellowness index
 LAB value

32. 1.39
1.4
1.41
1.42
1.43
1.44
1.45
1.46
1.47
1.48
0 3 6 9 12 15 18 21 24
% age of metal salt
Refractiveindex
M-1
 M-2
♦ M-3
EFFECT OF METAL SALTS ON
REFRACTIVE INDEX OF ACRYLIC PLASTICS
 Metal salts are effective in improving the refractive
index of acrylic plastics

33. EFFECT OF CO-MONOMER 1 ON REFRACTIVE
INDEX OF METAL DISPERSED ACRYLIC PLASTICS
1.4
1.42
1.44
1.46
1.48
1.5
1.52
0 2 4 6 8 10 12 14
%age of comonomer-1
Refractiveindex
 Significant increase in refractive index of acrylic plastic
is obtained with co-monomer 1
♦ M-1
 M-2
M-3

34. 1.38
1.4
1.42
1.44
1.46
1.48
1.5
1.52
1.54
1.56
0 2 4 6 8 10 15 20 25 30 35 40 45 50
%age of comonomer-2
Refractiveindex
EFFECT OF CO-MONOMER 2 ON REFRACTIVE
INDEX OF METAL DISPERSED ACRYLIC PLASTIC
♦ M-1
 M-2
M-3
 Significant increase in refractive index of acrylic plastic
is obtained with co-monomer 2

35. PROPERTIES OF GAMMA RADIATIATED
SAMPLES CO-MONOMER 1
 Dispersion of metal salts resulted in improved optical and mechanical
properties of polyacylates
1.1581.2181.044Yellowness index14.
858287Spectral Transmittance (%)12.
1.281.301.31Specific gravity11.
>120>120120.0Heat distortion (0C)10.
GoodGoodGoodMachinability9.
PassPassPassImpact resistance8.
4H3H3HPencil hardness7.
6.80-7.0710.7-10.88.24-8.29Haze6.
Grade-BGrade-BGrade-BScratch resistance5.
78-8070-7570-72Shore-D hardness4.
343435Abbe No.3.
1.581.591.56Refractive index2.
Light YellowDark YellowLight YellowColour1.
M-1 M-2 M-3
Metal dispersed polyacrylateAnalysisS.
No.
13. Integrated transmittance 0.5563 0.5575 0.5679

36. 0.1592
90
1.23
>120.0
Good
Pass
3H
---
Grade-B
88-90
38-39
1.5603
0.13920.1263Yellowness index14.
8987Spectral Transmittance (%)12.
1.291.24Specific gravity11.
130>120.0Heat distortion (0
C)10.
GoodGoodMachinability9.
PassPassImpact resistance8.
3H3HPencil hardness7.
---2.75-2.84Haze6.
Grade-BGrade-BScratch resistance5.
80-8285-88Shore-D hardness4.
30-3134Abbe No.3.
1.5741.570Refractive index2.
colourlesscolourlessLight yellowColour1.
M-1 M-2 M-3
Metal dispersed polyacrylateAnalysisS. No.
13. Integral Transmittance 0.5933 0.5822 0.7795
PROPERTIES OF GAMMA RADIATIATED
SAMPLES CO-MONOMER 2

37. STANDARD MATERIAL Vs METAL
CONTAINING SAMPLES
>2.02.03.0<1.01-2< 1.0Haze,%7.
>9092> 908990-9290-95Transmittance6.
1.20-1.301.241.331.201.322.0-5.0Specific gravity5.
GoodPoorModerateModerateGoodPoorImpact
resistance
4.
>85< 65>757588-89>90Shore-D
Hardness
3.
35-385726355850-55Abbe number2.
1.56-1.591.451.661.581.491.80Refractive index1.
PA
(SRI)
PAPTU
(SRI)
PCCR-39GlassPropertiesS.No
 Modified polyacrylates can be a good replacement to the
conventional optical materials

38. STANDARD MATERIAL Vs METAL
CONTAINING SAMPLES
0.12-1.20.022750.170.07860.00740.0087Yellowness
index
13.
0.5533-0.61520.58450.58580.59060.57911.1548Integrated
Transmittance
12.
GoodGoodGoodGoodGoodGoodMachinability11.
3H-4H3H6H3H4H>6HPencil
hardness
10.
Grade-BGrade-DGrade-BGrade-BGrade-BGrade-AScratch
resistance
9.
L=51.38-77.05
a=-6.25-7.50
b = 23.7-25.50
L=67.50
a=6.30
b=20.30
L=67.90,
a = 5.50,
b = 23.2
L=67.68,
a = 6.15,
b = 21.8
L=67.44,
a = 6.35,
b=20.32
L=67.46,
a = 6.35,
b=20.48
LAB value8.
PA
(SRI)
PAPTU
(SRI)
PCCR-39GlassPropertiesS.No
 Modified polyacrylates can be a good replacement to the
conventional optical materials

39. CONCLUSIONS
Materials can be designed for desired characteristics
Lenses have been cast successfully with barium ,lead
and lanthanum salts.
Tailor making of refractive index of polyacrylates have
been achieved between 1.550-1.575 using barium salts;
1.560-1.595 using lead salts; 1.550-1.565 using
lanthanum salts.
SRI team has been successful in developing metal
dispersed nano-composites of polyacrylate with
improved Abbe no., hardness, & scratch resistance.

40. FUTURE OF NANOTECHNOLOGY
Structure
sizes
2040 year1960 1980 2020Based on Bachmann, VDI
0.1 nm
0.1 µm
0.1 mm
Nano
Micro
Macro
Integrated
use of
biological principles,
physical laws
and chemical know-howComplex chemistry
Electrical engin.
Electronics
Micro-electronics
Material design
Supramolecular
chemistry
Quantum effects
Cell biology
Molecular
biology Functional
molecule design
Applications
of
nano-
technology
bottom upbottom up 
top
down
top
down

Chemistry
Coatings,
cleaning agents,
composite materials,
textiles,
cosmetics,
displays
Physics
Biology

41. THANK YOU