Advanced polymer nanocomposites: novel properties and applications

Advanced Polymer
Nanocomposites:
Novel Properties and Applications
Ramanan Krishnamoorti
Department of Chemical & Biomolecular
Engineering
University of Houston
ramanan@uh.edu

State of the Art: Aerospace
Applications of Nano
Thanks to Rich Vaia, AFRL

Outline
What are Polymer Nanocomposites? Uniqueness?
Length Scale, Interface, Number Density, Critical Concentration
How are They Made? Options?
Nanofillers, Nanoparticles, Synthesis, Interface Modification
Application Examples:
Automotive – Maintaining Performance to Provide Added Value
Barrier - Nano Filler as Part of Formulation
Flame Retardants - NanoFiller‟s Latent Role: Self-Passivation & Reinforcement
CFRF - Approach to “Engineered Materials”
Shape Memory - Impacting the “Dominant” Attribute of the Polymer
“DC” Electrical - NanoParticle Network and “Critical Junctions”
Dynamic Electrical - Network Responsivity
Dielectric – Field Distribution, Interfaces and Charge Trapping
Next Step: Single Phase PNCs
Summary and Conclusions

What is a Polymer Nanocomposite?
• Distinguishing Attributes?
• Perspectives
• Material Constituents?
• Property?
• Dominate Structural Motif?
• Application?

Definition
• IUPAC – Nanocomposite
• Composite in which at least one of the phases has at least one dimension of the order of
nanometers (PAC, 2004, 76, 1985, Definition of terms related to polymer blends,
composites, and multiphase polymeric, doi:10.1351/pac200476111985)
• Wikipedia – Nanocomposite
• Multiphase solid materials where one of the phases has one, two or three dimensions of
less than 100 nanometers (nm), or structures having nano-scale repeat distances
between the different phases that make up the material.
• In the broadest sense this definition can include porous media, colloids, gels and
copolymers, but is more usually taken to mean the solid combination of a bulk matrix and
nano-dimensional phase(s) differing in properties due to dissimilarities in structure and
chemistry.
• The mechanical, electrical, thermal, optical, electrochemical, catalytic properties of the
nanocomposite will differ markedly from that of the component materials.
• Size limits for these effects have been proposed,

Operational: Polymer
Nanocomposites
• Introduce small amounts of Nanoparticles to achieve dramatic
changes in
– Mechanical, Thermal, Physical, Electrical and / or Chemical Properties
– Introduce Multifunctionality (Structural + Electric; Structural +
ElectroMechanical; Structural + Permeability; Structural +
Biocompatibility)
– Minimal change in density of the polymer
– Possibly Inexpensive
• Challenges:
– Dispersion (Equilibrium; Kinetics; Processing)
– Interface Control
– Optimization & Pricing

► Nanoparticles
► Silica Nanoparticles
► Silsequioxanes
► Carbon nanotubes
► Layered silicates
► Isotropic or Anisotropic
Nanoparticles
► Usually possess Hierarchy of Structure
► Functionalized or Pristine
► Controls Thermodynamics
► Might Compromise Properties
1 nm
R
O
X
R
Si
O O
Si
O
Si
Si
O
R
O
O
Si
R
R
Si
O
O
O
Si
O
Si
O
R
R
100 nm

MRS Bulletin, April 2007
Occurrences per year
5000
4000
3000
2000
1000
0
NC
PNC
PNC with "Clay"
PNC with "Nanotube"
1985 1990 1995 2000 2005
PNC Trends
Fraction
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
PNC:NC
PNC Patents:PNC
PNC with "clay":PNC
PNC with "nanotube":PNC
1996 1998 2000 2002 2004 2006
Growth trends of the Polymer Nanocomposite enterprise based on yearly publications cataloged in
the CAPLUS and MEDLINE databases of the American Chemical Society 15 . a) Number of
occurrences per year of the term “Nanocomposite” (NC, �) and “Nanocomposite” with “Polymer”
(PNC, �). “Polymer Nanocomposites” is further refined to those discussing “clay” PNCs (�) and
“nanotube” PNCs (�). b) Analysis of the yearly number of citations showing the total fraction of
“Nanocomposite” occurrences that discuss “Polymer Nanocomposite” (PNC:NC, �) as well as the
total fraction of “Polymer Nanocomposite” occurrences that are patents (PNC Patents, �), discuss
clay based PNCs (PNC “clay”, �), and discuss “nanotube” containing PNCs (PNC “nanotube”, �).

Unique issues due to Nanoparticles
• Contrast a spherical particle with diameter 1 mm with
one with diameter 10 nm:
– At 10 vol % particles:
Particle diameter 10 nm 1 mm
# particles/ cc 1.9 x 10 17 1.9 x 10 11
Internal surface area / cc 60 m 2 0.6 m 2
Average Interparticle distance 8.5 nm 850 nm
Polystyrene: M w = 100,000 � R g(melt) = 8.5 nm

Reinforcement
�
10 mm �� 1
h
10 nm
Filled Polymer
l = 1 mm
Nanocomposite
l = 1 nm
Interfacial Region
� z �
Vaia, Materials Today, 2006;
Chemistry of Materials, 2007;
Science (Perspective), 2008
0
Critical Feature
R
g
Bulk
z �
R
g
Material of Interfaces
~700-800 m 2 /g (10 3 x )
Material of Fillers
~1 x 10 5 particles/mm (10 5 x)
Material of Associating Units
f C ~ 10 -3 – 10 -4
~ 10 nm @ 5-7 vol%
Opportunities
• Interface-to-volume ratio
• Unique Nanoparticle Prop.
• Heterogeneity less than ‘critical
flaw size’
• Emergent Behavior: associative
network of nanoelements

Caveats
Issues are not new Issues are not unique
Critical Aspects:
• Polymer NanoComposites?
Is this a „reinvention‟ of filled polymers?
• Hierarchical morphology – property correlations?
When is this not an issue?
• Confined polymer behavior?
Different from thin film and coating technology?
• Filler impact polymer meso phase?
Crystallization aids & process dependent crystal fraction?
Preponderance of interface 700 m 2 /g
Diminishing small volume fraction of „bulk‟ d ~ Rg
Aspect ratio of constituents a > 100
Dissimilar mechanical properties Ef/Em ~ 10 3
Hierarchical morphology has one more scale CF(nm-mm; q)

First Commercial Nanocomposite
Nylon 6 from Toyota Central RD
Property Changes
NCH (5wt%) Nylon-6
Tensile Modulus (GPa) 2.1 1.1
Tensile Strength (MPa) 107 69
Heat Distortion Temp. ( o C) 145 65
Impact Strength (kJ/m 2 ) 2.8 2.3
Water Adsorption (%) 0.51 0.87
CTE (x,y) 6.3 x 10 -5
13 x 10 -5
Peak Heat Release Rate (kW/m 2 ) 378 1011
Okada et al. Mat. Sci. Eng. 1995, C3, 109.
Gilman et al. SAMPE, May 1998
The clays are 1 nm in thickness and 100-500 nm in diameter

Review Articles (I)
• “Polymer/layered silicate nanocomposites: a review from preparation to processing” Ray, S. S.;
Okamoto, M. Prog. Polym. Sci. 2003, 28, 1539-1641.
• “Polymer nanocomposite foams” Lee, L. J.; Zeng, C.; Cao, X.; Han, X.; Shen, J.; Xu, G. Composites
Science and Technology 2005, 65, 2344-2364.
• “Polymer Nanocomposites Containing Carbon Nanotubes” Moniruzzaman, M.; Winey, K. I.
Macromolecules 2006, 39, 5194-5205.
• “Polymer/montmorillonite nanocomposites with improved thermal properties Part I. Factors
influencing thermal stability and mechanisms of thermal stability improvement” Leszczynska, A.;
Njuguna, J.; Pielichowski, K.; Banerjee, J. R. Thermochimca Acta 2007, 435, 75-96.
• “Synthetic, layered nanoparticles for polymeric nanocomposites (PNCs)” Utracki, L. A.; Sepehr, M.;
Boccaleri, E. Polym. Adv. Technol. 2007, 18, 1-37.
• “Bionanocomposites: A New Concept of Ecological, Bioinspired, and Functional Hybrid Materials”
Darder, M.; Aranda, P.; Ruiz-Hitzky, E. Adv. Mater. 2007, 19, 1309-1319.
• “Twenty Years of Polymer-Clay Nanocomposites” Okada, A.; Usuki, A. Macromol. Mater. Eng. 2007,
291, 1449-1476.
• “Polymer Nanocomposites with Prescribed Morphology: Going beyond Nanoparticle-Filled
Polymers” Vaia, R. A.; Maguire, J. F. Chem. Mater. 2007, 19, 2736-2751.
• “Applications of hybrid organic-inorganic nanocomposites” Sanchez, C.; Julian, B.; Belleville, P.;
Popall, M. J. Mater. Chem. 2005, 15, 3559-3592.
• “How Nano are Nanocomposites?” Schaefer, D. W.; Justice, R. S. Macromolecules 2007, 40, 8501-
8517.
Alex Morgan, University of Dayton

Review Articles (II)
• “Features, Questions, and Future Challenges in Layered Silicates Clay Nanocomposites with Semicrystalline
Polymer Matrices” Harrats, C.; Groeninckx, G. Macromol. Rapid Commun. 2008, 29, 14-26.
• “From carbon nanotube coatings to high-performance polymer nanocomposites” Bredeau, S.; Peeterbroeck, S.;
Bonduel, D.; Alexandre, M.; Dubois, P. Polym. Intl. 2008, 57, 547-553.
• “Polymer Nanocomposites” Krishnamoorti, R.; Vaia, R. A. J. Polym. Sci: Part B: Polym. Phys. 2007, 45, 3252-3256.
• “Nanocomposites based on polyolefins and functional thermoplastic materials” Ciardelli, F.; Coiai, S.; Passaglia,
E.; Pucci, A.; Ruggeri, G. Polym. Int. 2008, 57, 805-836.
• “Flame retarded polymer layered silicate nanocomposites: a review of commercial and open literature systems”
Morgan, A. B. Polym. Adv. Technol. 2006, 17, 206-217.
• “Polymer nanotechnology: Nanocomposites” Paul, D. R.; Robeson, L. M. Polymer 2008, 49, 3187-3204.
• “Processing of nanographene platelets (NGPs) and NGP nanocomposites: a review” Jang, B. Z.; Zhamu, A. J.
Mater. Sci. 2008, 43, 5092-5101.
• “Colloidal nanocomposite particles: quo vadis?” Balmer, Jennifer A.; Schmid, Andreas; Armes, Steven P. J. Mater.
Chem. 2008, 44, 5722 – 5730
• “Toxicity Evaluation for Safer Use of Nanomaterials: Recent Achievements and Technical Challenges” Hussain, S.
M.; Braydich-Stolle, L. K.; Schrand, A. M.; Murdock, R. C.; Yu, K. O.; Mattie, D. M.; Schlager, J. J.; Terrones, M. Adv.
Mater. 2009, 21, 1549-1559.
Alex Morgan, University of Dayton

Outline
What are Polymer Nanocomposites? Uniqueness?
Length Scale, Interface, Number Density, Critical Concentration
How are They Made? Options?
Nanofillers, Nanoparticles, Synthesis, Interface Modification
Application Examples:
Automotive – Maintaining Performance to Provide Added Value
Barrier - Nano Filler as Part of Formulation
Flame Retardants - NanoFiller‟s Latent Role: Self-Passivation & Reinforcement
CFRF - Approach to “Engineered Materials”
Shape Memory - Impacting the “Dominate” Attribute of the Polymer
“DC” Electrical - NanoParticle Network and “Critical Junctions”
Dynamic Electrical - Network Responsivity
Dielectric – Field Distribution, Interfaces and Charge Trapping
Next Step: Single Phase PNCs
Summary and Conclusions

Nanocomposite
Hybrid
Lane UMich, Lichetenhan
Hybrid
Approaches: Organic-Inorganic
Nanostructured Materials
A. Exfoliation
Nanocomposites
B. In-situ formation (templating)
IPNs, mesoporus hybrids
C. Molecular incorporation
POSS, CERAMERs
Peng, et al. Science.
2000, 1802. Kramer, Hawker, etal
Wiesner et al Cornell
Matyjaszewski, K.., CMU

Traditional Fillers
Carbon Black
Carbon Fiber Rods
Approximate
Shape*
Agglomerate of
Spheres
Smallest
Dimension
(nm)*
Aspect
Ratio**
Elastic
Modulus
(GPa)
Electrical
Conductivity
(S/cm)
Thermal
Conductivity
(W / mK)
Commercial Uses
10-100 1 - 5 na 10-100 0.1-0.4 tires, hoses, shoes, elastomers
5,000-
20,000
10-50 300-800 0.1-10 100-1000
aerospace, automotive, marine, sporting,
medical
Carbon Graphite Plate 250-500 15-50 500-600 1-10 100-500 gaskets, seals
E-Glass Rod
Mineral: CaCO 3
Mineral: Silica
Mineral: Talc, China
Clay
Nanoscale Fillers
Sphere Platelet
Agglomerate of
Spheres
Platelet
10,000-
20,000
45-70
600-4,000
8,000-
30,000
5,000-
20,000
20-30 75 na na marine, automotive, construction, filtration
~1
1-30
35 na 3-5 paper, paint, rubber, plastics
5-10 30-200 na 1-10
reinforced plastics, thermal insulator, paint,
rubber reinforcing agent
5-10 1-70 na 1-10 paper, consumer goods, construction
Carbon NanoFiber Rod 50-100 50-200 500 700-1000 10-20
Carbon MWNT Rod 5-50
Carbon SWNT Rod 0.6 - 1.8
NanoGraphite /
Graphene
Aluminosilicate
Nano-Clay
100-
10000
100 -
10,000
hoses, aerospace, ESD/EMI shielding,
adhesives
1,000 500-10,000 100-1000 automotive, sporting, ESD/EMI shielding
1,500 1000-10,000 1000 filters, ESD/EMI shielding
Plate 0.4-10 100-1000 1,000 1000-10000 1000 ESD/EMI shielding
Plate 1-10 50-1000 200-250 na 1-10
automotive, packaging, sporting, tires,
aerospace
Nano TiO2 Sphere 10-40 ~1 230,000 10-11-10-12 12 photocatalysis, gas sensors, paint
Nano Al2O3 Sphere 300 ~1 50 10-14 20-30
seal rings, furnace liner tube, gas laser
tube, wear pads
Nano-Cellulose
Common Fillers and Nanoparticles:
Rod 10-100 ~100 100-200 10 -12 1-10
construction, automotive, commercial
Winey & Vaia, MRS Bulletin, 2007

Equilibrium States
d
Unmixed
D
Intercalated
Exfoliated

SWNT Rope
Synthesis Approaches
►Melt Intercalation: Co-Extrusion
► Functionalization of the NPs*
SWNT
�Tailoring the modifier to the polymer promotes favorable interactions
O
O
Organic Modifier
► In-Situ polymerization with pristine** or functionalized NPs
� or hn
► Surfactant assisted dispersion of NPs***
O H
* Mitchell, C.A., Bahr, J. L., Arepalli, S., Tour, J., Krishnamoorti, R. Macro. 2002, 35, 8825-8830
**Putz K., Mitchell C. A., Krishnamoorti R., Green P. F. J. Polym. Sci. Part B: Polym. Phys., 42, 2286 – 2293 (2004).
**Parekh, B. , Tangonan A., Newaz, S. S., Sanduja, S. K., Ashraf A. Q., Krishnamoorti, R. , Lee, T. R., Macro, 2004.
***Yurekli K., Mitchell C. A., Krishnamoorti R., J. Am. Chem. Soc.,, 2004, 126(32), 9902-9903.
n

Synthesis Approaches
References Restricted to Clays
Melt Intercalation:
Polystyrene (PS) [Macromolecules 30 (1997) 8000; Chem. Mater. 5 (1993) 1694]
Nylon-6. [J. Appl. Polym. Sci. 71 (1999) 1133]
Polypropylene with maleic anhydride (PP-MA) or hydroxyl (PP-OH) [J. Appl. Polym. Sci 66 (1997) 1781;
Macromolecules 30 (1997) 6333; J. Appl. Polym. Sci 67 (1998) 87]
Poly(styrene-b-butadiene) copolymer (SBS) [J. Mater. Res. 12 (1997) 3134]
Poly(dimethylsiloxane) (PDMS) [Chem. Mater. 7 (1995) 1597; J. Appl. Polym. Sci. 69 (1998) 1557]
Nitrile rubber (NBR) [Mater. Sci. Eng. C3 (1995) 109]
Poly(ethylene oxide) (PEO) [Adv. Mater. 7 (1995) 154]
Solution Intercalation:
poly(vinyl alcohol) (PVOH) [J. Colloid Sci 18 (1963) 647; J. Appl. Polym. Sci. 66 (1997) 573],
poly(ethylene oxide) (PEO) [Clay Mineral 8 (1970)305. Colloid Polym. Sci 267 (1989) 899, Adv.Mater. 7 (1995)]
poly(lactide) (PLA) [J. Polym. Sci.: Part B: Polym. Phys. 35 (1997) 389]
poly(e-caprolactone) (PCL) [J. Appl. Polym. Sci 64 (1997) 2211]
poly(imide) (PI) [J. Polym. Sci.: Part A: Polym. Chem. 31 (1993) 2493, ibid 35 (1997) 2289]
In-Situ Polymerization:
Interlayer polymerizations: Appl. Clay Sci. 15 (1999) 109.
Nylon-6 [ Clay Mineral, 23 (1988) 27; J. Mater. Res. 8 (1993) 1179; J. Mater. Res. 8 (1993) 1174; J. Polym. Sci.
Part A: 31 (1993) 983;J. Polym. Sci Part A: 31 (1993) 1755]
poly(e-caprolactone) (PCL). [J. Polym. Sci.: Part A 33 (1995) 1047. Adv. Polym. Sci. 147 (1999) 1; J. Macromol.
Sci.-Rev. Macromol. Chem. Phys. C35 (1995) 379]
Polystyrene (PS) [J. Am. Chem. Soc. 121 (1999) 1615]
HDPE [WO Patent WO9947598A1 (1999); J. Macromol. Sci.: Rev. Macromol. Chem. Phys. C38 (1998) 511]
(Co)polyolefin [Macromol. Rapid Commun. 20 (1999) 423]
Poly(ethylene terephtalate) (PET) [J. Appl. Polym. Sci. 71 (1999) 1139]

Outline
What are Polymer Nanocomposites? Uniqueness?
Length Scale, Interface, Number Density, Critical Concentration
How are They Made? Options?
Nanofillers, Nanoparticles, Synthesis, Interface Modification
Application Examples:
Automotive – Maintaining Performance to Provide Added Value
Barrier - Nano Filler as Part of Formulation
Flame Retardants - NanoFiller‟s Latent Role: Self-Passivation & Reinforcement
CFRF - Approach to “Engineered Materials”
Shape Memory - Impacting the “Dominate” Attribute of the Polymer
“DC” Electrical - NanoParticle Network and “Critical Junctions”
Dynamic Electrical - Network Responsivity
Dielectric – Field Distribution, Interfaces and Charge Trapping
Next Step: Single Phase PNCs
Summary and Conclusions

UBE Nylon 6 Toyota timing belt cover; engine manifold cover
Nylon 6 Film for packaging
Nylon 6/66, 12 Fuel system components
Bayer Nylon 6 Film for meat packaging
Nylon 6 coating for paper board juice container
PC/ABS Flame retardant computer and monitor housings
Foster Corp. Nylon 12 nanocomposites used in catheter tubing
GM Polyolefin TPO for step on Astro vans to replace talc filled material.
Will be integrating into other parts in near future.
Unitika Nylon 6 automotive parts (Mitsubishi engine cover)
EVOH, Polylactic acid
Wilson Sporting Tennis balls (nanoclay/butyl rubber coating from InMat)
Honeywell Nylon 6 for food packaging
US Army MRE food tray (EVOH)
Example Commercial Ventures:
Polymer-Clay Nanocomposites
Kablewerk Eupen EVA flame retardant cable coating
TNO polyurethane binding system for ceramic molds
RTP Various polyamides and polyolefin concentrates
Triton Systems Polyurethane bladder for athletic shoe
Polyolefin packaging films for food and pharmaceutical packaging
Nanocor MXD-6 Nylon for barrier food packaging
Beall, 2002

August 01
Feb 04
• Side trim modeling Impala
• Trim and panel applications
Hummer H2
MRS Bulletin, 2007, vol 32
First Commercial Nano TPO
Step Assist on Astro and Safari Van
GM/Basell/Southern Clay Products/Blackhawk
Commercialization Factors:
• Mass savings
• Lower specific gravity
• Lighter weight reduces cost and requires less
adhesive for attachment
• Large processing window
• Consistent physical and mechanical properties
• Elimination/reduction of tiger striping
• Improved appearance
• Improved knit line appearance
• Improved colorability and painting
• Sharper feature lines and grain patterns
• Improved scratch/mar resistance
• Low temperature ductility
• Improved recyclability

Polymer Nanocomposites: Automotive
Reducing weight improves gas mileage, which also reduces emissions – 25 kilograms means a
one percent increase in fuel Economy…”
Timothy P. McCann, Vice President Sales & Marketing, DuPont Engineering Polymers, DuPont press conference, Pre-K 2007 in
Prague, DuPont Engineering Polymers’ vision 2010
“Nanocomposites provide a means to achieving equivalent properties at lower glass loadings
which opens the way for reducing the weight of parts with comparable properties while
providing other attributes, such as improvements in surface appearance.”
Nandan Rao, Technology Director for DuPont Performance Materials DuPont press conference, Pre-K 2007 in Prague, Shaping the Future of
Plastics: New Technology Platforms
“Thermoplastic olefin - clay hybrids (TPO-CH), e.g.
the composite based on approx. 5 weight-%
montmorrillonite (MMT) dispersed in flakes of the
smallest structural level in TPO, have the potential of
being a suitable material for automotive composite
body panels. Commercial such materials have been
investigated at Volvo Cars “
Magnus Oldenbo, Volvo car Company, and Xavier Kornmann, Luleå University
of Technology, Sweden

Permeability Reduction
How do Anisotropic Nanoparticles Influence the
Permeability of Gases through a Polymer?
What are the appropriate issues to consider?
What are potential complications?
The Converse All-Star
He:01
Converse Basketball Shoe
Triton Systems Developed
Nanocomposites
Triton’s NanoFilament
Cushioning Device
Nanocomposite Pouch filled with Helium

Nanocomposites for Enhanced
Influence of Layered Silicate on Permeability
Impermeability
Layered
Impermeable
aspect ratio a
Relative Permeability P/P 0
1.0
0.8
0.6
0.4
0.2
500
a = 100
a = 25
a = 10
0.0
0 0.04 0.08 0.12
Volume Fraction f
Cussler et al. J. Memb Sci., 1998

Why O 2 Permeability through An
Elastomer
Replacement of Traditional Inner-liners with Nanocomposite Inner-liners (50 %
reduction in permeability) would result in a decrease of ~ 4 lbs per truck tire
(conservative estimate)
� 2 % Fuel Efficiency improvement.

Structure of as-prepared Layered-
Silicate Nanocomposite

P / P o (oxygen flux)
Role of Nanocomposite Structure
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
a ~ 100
on O 2 Permeability
Steady – State Flux
Intercalated 2C18M
Exfoliated / Disordered
Exfoliated
0.00 0.02 0.04 0.06 0.08 0.10
wt. fn Montmorillonite
Isobutylene Copolymer
Oxygen Permeability at 25
o C
No – Crosslinking
Intercalated
Exfoliated
D

P / P o (oxygen flux)
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
Effect of Orientation on
Permeability: Exfoliated System
0.0 0.2 0.4 0.6 0.8 1.0
Random Aligned
Anisotropy Factor
PIB Based Copolymer
Organically Modified
Montmorillonite –
Exfoliated
Nanocomposite
5 wt. % Montmorillonite
a is ~ 100, Not 500!
5 fold decrease in the permeabiilty of O 2 through the inner-liner material

Outline
What are Polymer Nanocomposites? Uniqueness?
Length Scale, Interface, Number Density, Critical Concentration
How are They Made? Options?
Nanofillers, Nanoparticles, Synthesis, Interface Modification
Calibrating Expectations – e.g. Mechanical and ViscoElastic
Application Examples:
Automotive – Maintaining Performance to Provide Added Value
Barrier - Nano Filler as Part of Formulation
Flame Retardants - NanoFiller‟s Latent Role: Self-Passivation & Reinforcement
CFRC - Approach to “Engineered Materials”
Shape Memory - Impacting the “Dominate” Attribute of the Polymer
“DC” Electrical - NanoParticle Network and “Critical Junctions”
Dynamic Electrical - Network Responsivity
Dielectric – Field Distribution, Interfaces and Charge Trapping
Next Step: Single Phase PNCs
Summary and Conclusions

Nano-Enabled Carbon Fibre Reinforced Carbon (CFRC)
Composites

Delivery of the NanoElement
•Resin
•Infusion
•Fiber Interface (Sizing)
•Interlamellar
•Individual Ply
•Veil
•Resin Film
•Fiber
•Adhesive
NanoComposites in CFRC?
37
©2003 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning is a trademark used herein under license.
©2003 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning is a trademark used herein under license.
Figure 16.13 A three-dimensional weave for fiberreinforced
composites.

©2003 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning is a trademark used herein under license.
Figure 16.23 Producing composite shapes by filament winding.
51
©2003 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning is a trademark used herein under license.
Figure 16.24 Producing composite shapes by pultrusion.
NanoComposites in CFRC?
©2003 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning is a trademark used herein under license.
Figure 16.21 Production of fiber tapes by encasing fibers
between metal cover sheets by diffusion bonding.
49
©2003 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning is a trademark used herein under license.
Figure 16.22 Producing composite shapes in dies by (a)
hand lay-up, (b) pressure bag molding, and (c) matched die
molding.

Table 1
Nano-Enabled CFRC
Property Common Nanocomposite Approach Potential Application
Physical/Chemical
Permeability Inclusion of impermeable, high aspect ratio silicate or graphite Cryogenic tanks, durability to
flake in resin
diffusion species
Outgassing Inclusion of impermeable, high aspect ratio silicate or Optical benches, interferometer,
graphene in resin
antenna truss structures
Oxidative Incorporate high temperature, oxidative resistant fillers Thermal protective systems,
Resistance
Electrical
(silicate, CNT,POSS, etc.) that form passivating layers or slow atomic oxygen resistance
oxidative erosion in resin or as coating
ESD Incorporate high aspect ratio conductive particles such as
CNT, graphite flake, metals, etc as percolated network in
resin between conductive fibers
Adhesives, coatings, gap fillers
EMI Create films of highly percolated network of conductive Bus compartment enclosure,
nanofillers (nickel nanostrand veil, SWNT buckypaper, etc.)
that can both absorb and dissipate broadband frequencies
electronic enclosures
Lightning Incorporate conductive nanofillers (nickel nanostrands, CNT, Composite aircraft exterior
Strike etc.) as highly percolated coatings, appliqués, resins, or veils
that can carry large currents and have controlled failure modes

Property Common Nanocomposite Approach Potential Application
Thermal
Thermal
Conductivity
Thermal
Protection
Systems
Coefficient of
Thermal
Expansion
Incorporate highly thermal conductive particles (CNT’s, metals,
etc.) into resin and optimize structure for heat transfer along
continuous path to heat sink
Use thermally conductive and insulating nanofillers within resin
to assist larger structure components to direct heat away from
protected systems
Incorporate nanofillers with low expansion coefficients and good
matrix bonding such as (functionalized CNT, CNF, silicates, etc.)
into resin or as fiber sizing to reduce CTE mismatch with fiber by
composite effect and restriction of polymer motion
Mechanical
Toughness Incorporate nanofillers like CNT into resin to increase energy
dissipation on failure through deformation, pull-out, crack
bridging, etc. at needed plies
Modulus Incorporate high modulus nanoparticles like continuous CNT
yarns/sheets as reinforcement or grow reinforcements between
plies to increase out of plane modulus
Compression Incorporate high strength nanoparticles such as functionalized
Strength carbon nanotubes into the resin
Interfacial Shear Grow high strength nanoparticles such as CNT from fiber to tailor
Stress
Interlaminar
Shear Strength
Nano-Enabled CFRC
the interfacial properties as a smart sizing
Incorporate nanofillers like CNT that can increase energy
dissipation on failure through deformation, pull-out, crack
bridging, etc. into resin at mid plies via coating or prepregging
Adhesives, gaskets, radiators,
doublers, electronics board, solid
state laser heat removal
Aircraft brakes, re-entry vehicles,
missiles
Adhesives, space apertures
Membrane structures, damage
tolerant structures
Precision stable structures
Propulsion tanks, fittings
High temperature composites,
vehicle health monitoring
Tubular structures

Composite With Nanostrands
One typical lay-up, here a veil is used in conjunction with Ni coated carbon fiber layer
Alexander et al., Air Force Research Lab
Nanostrand veil
X ply
Ni coated cloth
Y ply
Base composite

Composite With Nanostrands

www.boedeker.com
Conductive NanoComposite
Elastomers
Volume Resistivity (W-cm) = 1 / Volume Conductivity (S cm -1 )
• Broad range of conductivity lead to
broad range of applications (EMI,
ESD, electrostatic painting,
transparent electrodes, etc..)
• Methodology:
– Multi-Phase Systems (Blends)
– Cond. Phase relatively rigid
– Percolation, Directed Morphology
• Lower volume fraction conductive
phase, enhances
– processing
– mechanical (elasticity)
– optical (clarity/absorption)
– cost
– stability
• Conductivity(external variable)
– mechanoreceptor
– induced polarization for actuator
– electrically stimulate shape memory

Stress (Psi)
140
120
100
80
60
40
20
0
SWNT Elastomer Nanocomposites
Dispersed SWNTs in Silicone Elastomer and subsequently Cross-linked w/Tour
Both functionalized and non-functionalized Elastomers
PDMS - SWNT Networks
T = 25 o C
Control (0 wt % SWNT)
Nanocomposite
(0.7 wt % SWNT)
0 200 400 600 800
Strain
Conductivity (s/cm)
10 -3
10 -4
10 -5
10 -6
10 -7
10 -8
RK
Normalized Tensile Modulus
50
40
30
20
10
0
T = 25 o C
0.0 0.5 1.0 1.5 2.0 2.5 3.0
0
3.5
Elongation (e)
0.7
Elongation at Break
Normalized Tensile Modulus
0.6
1
0 1 2 3
0.5
0.4
0.3
0.2
0.1
Herman's Orientation Parameter
wt % SWNT
9
7
5
3
Strain at Break

SWNT based Elastomer
Nanocomposites
� Fractal structure of SWNTs leads to interpenetrating
networks and extraordinary properties
� Unfunctionalized SWNT nanocomposites exhibit
multifunctionality (self-sensing)
�Broad-range of applications are possible:
�Nanocomposites Inc. with Hydril: Use of reinforced
elastomers (nitrile) for oil and gas production in Blow
Out Protectors.

Bulk Bulk DC DC Conductivity Conductivity (S/cm) (S/cm)
Conductive NanoTube-filled Elastomer
10 1
10 1
10 -1
10 -1
10 -3
10 -3
10 -5
10 -5
Effective EMI Shielding Level
Treated Nanotube #2
in Morthane (one data point)
Carbon Nanotube #1
Morthane TPU
Carbon Nanotube #2
Estane
0 2 4 6 8 10 12 14 16 18 20 22
M. Alexander, Koerner, et al.
s = s o |f-f c| t
Volume % Carbon Nanotubes
f c = 0.005
s 0 = 6.3 kS/cm
t = 3.1
“Nanocomposites”
f c ~ 0.5-1%
s ~ 0-100 S/cm

Shape Memory Polymers
Reversible „Phase‟ or Morphology Change
1) alters volume (or rigidity),
•Order-Disorder Transition
•Nematic – Isotropic
•Miscible-Immiscible
2) „traps‟ strain energy by retarding
recovery
•Glass Transition
•Strain-induced crystallization
e(T �); T�
T�
e
T�
Cornerstone
Research
Group, Inc.
*Gall, K., Kreiner,
P., Turner, D., and
Hulse, M.,
Journal of
MicroElectro
Mechanical
Systems, 2003

Heat ~50 o C
1% CNT/elastomer
composite
Shape-Recovery
l = 3
l = 8
t movie = 2*t

Shape-Recovery
IR Light Current
1% CNT/elastomer composite
Internal Heat
Generation
Thermal Initiated
Chemistry
Out-of-autoclave cure
Microfabrication
Machining
Joining
Core-shell formation
Koerner, Vaia, Nat. Material 2004

% Shape Fixity
(e x 100/e )
set max
% Recovery
([e -e ]100/e )
set recov max
100
98
96
94
92
80
75
70
65
60
SMP: Thermoset (epoxy-base*), Tg-Strain Set
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Volume Fraction (%)
D. Powers et al 2007
Composite
Flat Panel
Steve Arzberger et al
Antenna Stiffener
Stowed Coupon
Deployed
Coupon
TEMBO ® Popout
Stiffener

‘Active’ Electro-Mechanical
Nanocomposites
Nanoparticle Network: „Topology‟
Log Conductivity
Actuation Sensors
fc Critical Filler
Concentration
Compliant
Electrodes
s = s o |f-f c| t for
f>f c
0 Filler Volume Percent 100
Opportunities:
Extensive Surface Area
• Control crystallization
• Improved processibility
Mechanical Reinforcement
• Low volume addition
• Improved output stress
Increased Dielectric Response
• Reduced actuation voltage
„Nano-Capacitor‟
Extended electrodes
Local-field effects
• Highly polarizable units
• Match resonance frequency
Novel actuation mechanisms
• Optical triggers
• Volume change
• Tunability

Current Smart Materials: SOA
Various sources: DARPA,Madden etc.

Current Smart Materials: Limitations
Polymeric Advantages
•Form, Shape, Processing
•Large deformation
•Multiple Processes
Polymeric Challenges
•Inadequate recovery force and
work density
•High activation voltages & Small
stress (low dielectric)
•Stimuli nominal restricted
(voltage or external heating)
•Restricted operation
temperatures and frequencies
•Limited development of
additional ‘functionality’
EAP
Polyurethane (Deerfield)
Silicone(Dow Corning)
PVDF-based
electrostrictors
PVDF and copolymers
Achieved
strains
(%)
11
100
5
10
>10
~0.1 1
Madden et al. 2004, 2007

I(2q) (au)
Electromechanical Nanocomposites
X-ray Diffraction
--> � Phase formation Sensor
(020/100)
(110)
0.003
0.0025 (021)
PVDF
0.25clay
0.5clay
0.25 clay-0.25 SWNT
10 15 20 25 30 35
100 nm
With Ounaies, and Vaia
Strain
V
2q (l = 1.371 Å)
0.002
0.0015
0.001
0.0005
0
1
Δt
t
2
3
PVDF
Nanocomposites
SWNT +
Montmorillonite clay
Storage Modulus (Mpa)
0 0.02 0.04 0.06 0.08 0.1 1000 0.12 0.14 0.16 0.18
0.0 0.5 1.0 1.5 2.0
Electric field (MV/m)
3500
3000
2500
2000
1500
Stress (MPa)
V
100
80
60
40
w
20
t
L
Mechanical Properties
2
1
3
0
0 25 50 75 100 125 150
SWNT vol%
PVDF
PVDF +
0.5 wt % SWNT
Strain (%)

Conductive NanoParticle Soft-Matter
Conductive Lubricants
for MEMs (current
program with BT, LDF
06)
Conductive, Solventfree
Inks for Flex-
Electronic Fab.; RF ID
tags and Antennas
Compliant
Electrodes
Contacts
RF in RF out
Contact
RF in RF out
Others: Medical Devices; Nastic / Vascular Material Concepts – functional fluid; Active Nano/Micro Fluidics – active
fluid; Net-Shape Ceramic Processing – particle deliever and green-body mechanics; Nano-Energetics –
processing, green-body mech, reactivity; Memory devices (single np charging); etc..

Pure CNT Materials

SWNT, surfactant,
PVA
SWNT, „LiC12SO4‟, PVA
1 cm/min
SWNT Fibers
Coagulate
Remove PVA
Vigolo, B. et al. Science 290, 1331–1334 (2000)
Partial
Coagulate
Gel
70 cm/min Acetone,
Dalton, A.B. Nature, 423, 703.
Also: GaTech/Rice, Windle, Team: S. Kumar et al. 2002-
Dry
Dalton, A.B. Nature, 423, 703.

Tensile Strength [ksi]
2000
1800
1600
1400
1200
1000
800
600
400
200
0
SWNT Fibers
Phase I
Target
Phase II
Targets
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140
Tensile Modulus [Msi]
Hexcel
Japanese PAN
LargeTow
Pitch-Based

Bottom Line: Polymer Nanocomposites
• PNCs are a “unifying bridge” concept
• Understanding enriched when placed in context
• Utilization determined by:
• Value add to application -- not maximum property
• property suite – processing – uniformity – cost
• Today: Mechanical & Plus
• Future: Plus & Mechanical
• Challenge:
• Inadequate quantification limits understanding (classic &
continuum v. “nano-effect”)
• What is ultimately possible?
• What is primary determining factor?
• Uniformity + Predictability = Manufacturability