Dr. Joycelyn Harrison presents an overview of her program - Low Density Materials - at the AFOSR 2012 Spring Review.

1. Low Density Materials
09 MAR 2012
Joycelyn S. Harrison
Program Manager
AFOSR/RSA
Integrity  Service  Excellence Air Force Research Laboratory
24 February 2012 DISTRIBUTION A: Approved for public release; distribution is unlimited. 1

2. 2012 AFOSR SPRING REVIEW
NAME: Low Density Materials
PORTFOLIO DESCRIPTION :
Transformative research targeting advanced materials that enable
substantial reductions in system weight with enhancements in
performance and function.
Research within the portfolio is focused on INCREASING the
SPECIFIC PERFORMANCE of aerospace platforms.
PORTFOLIO SUB-AREAS:
Structural Lightweighting
Multifunctionality
Hybrid Materials
Increased emphasis on forging interdisciplinary
teams to address broad-base challenges
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3. Why Low Density Materials?
If it has structure and rises above the ground,
material density is important!
Material density impacts: payload capacity, range, cost,
agility, survivability, environmental impact….
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4. Increasing Specific Performance
in Aerospace Platforms
Specific Performance
Performance * r -1
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5. Polyimide Nanofiber Reinforced Structures
Dr. Yuris Dzenis
Novel Material Synthesis McBroom Professor
Incorporating steric hindances and reduced
chain periodicity to achieve:
- Organo-solubility
- Structural rigidity and toughness Dr. Stephen Cheng
- High thermal stability NAE
Robert C. Musson
Trustees Professor
Dr. Frank W. Harris
Distinguished
Professor
Emeritus
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6. Nanofiber Reinforced Structures
High Strength, Tough Polyimide Nanofibers
9000 Tensile Strength Vs Fiber Diameter
Advanced carbon fiber
Ultimate Tensile Strength (MPa)
8000
7000
6000
5000
4000
3000
2000
1000
0
0 100 200 300 400
Fiber Diameter (nm)
3000 Toughness Vs Fiber Diameter
2500
Toughness (MPa)
2000
1500
Continuous nanofibers electrospun
1000
from novel, soluble polyimide 500
8.7 GPa strength 0
47% failure strain 0 100 200
Fiber Diameter (nm)
300 400
2,500 MPA toughness
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7. Translation of Nanoscale Properties
to Macroscale Structures
Fundamental Challenge:
Improving CNT-CNT Load Transfer
Dr. Ben Wang
Fellow – IIE, SME, SAMPE
Densely Packed,
Alignment Flattened CNTs
Dr. Richard Liang
CNT Bundles DISTRIBUTION A: Approved for public release; distribution is unlimited. 7

8. CNT-CNT Reaction Mechanisms
Fundamental Challenge: CNT-CNT Bonding
Crosslinking MWCNTs via
Covalent Bonds
A. V. Krasheninnikov, K. Nordlund, “Ion and
Electron Irradiation-Induced Effects in
Nanostructured Materials,” J. Appl. Phys. 107,
071301, 2010
Irradiation-induced Crosslinking of CNTs
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9. Training Tomorrow’s Workforce
(AFOSR DURIP 11) Acquisition of a
Thermal Field Emission Scanning
Electron Microscope
Nanoparticle Reinforced Resins for Readily
Processable, High Temperature, Low Density Dr. David Veazie
• 2010 AFRL Summer
Composites and Energetic Materials Faculty Fellow at
AFRL/RW
“The SEM will meet the increasingly stringent • National Technical
requirements of cutting-edge materials Achiever of the Year
technology for fundamental research and the
education and research training of students.”
SEM of 0.3 wt% graphite/PETI-298,
confirming the dispersed graphene DISTRIBUTION A: Approved for public release; distribution is unlimited. 9

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11. Multifunctionality: CNT Fibers
Liquid Phase Processing of CNTs
Dr. Matteo Pasquali
Cryo-TEM CNT/ Polarized light micrograph of 10 mm Technology
chlorosulfonic acid dispersion CNT/chlorosulfonic acid dispersion Transfer
Research in
Typical Acid Spun Fiber
collaboration
with Teijin Aramids
37±3µm
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12. Multifunctionality
Load-bearing + Electrical Conductivity
3 LED wired and held by
2.5 “invisible” CNT fibers
Tensile Strength/Density
PAN C fiber
Mm2/s2 or N/Tex
2 Pitch C fiber
Ni-coated
1.5 PAN C fiber
RICE CNT fiber
1
0.5 Steel Aluminum
Silver
Nickel Gold Copper
0
0 5 10
Electrical conductivity/density (kS m2 / kg) 15
• Best electrical conductivity reported for neat CNT fibers
• Order of magnitude increase in electrical & thermal conductivity and strength
Research in collaboration of Teijin Aramids
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13. Enabling Multifunctionality:
Graphene Nanocomposites
Non-covalent functionalization of graphene in solution
GRAPHITE
OUR METHOD: NON-
STATUS QUO: COVALENT
OXIDATION STABILIZATION1
Stabilizers:
Dr. Micah Green
GRAPHENE
• 2010 AFOSR Young
OXIDE PRISTINE
Investigator Award
GRAPHENE
PVP π-π stackers
Dispersions are stable against pH
Advantages:
changes, heat, lyophilization
Disadvantage: Retains conductivity,
Insulating, oxidative debris stabilizer can be tailored
to application
Physisorption of PVP on graphene surface
guarantees excellent interfacial load transfer1
1Wajid et al, Carbon, 2012 DISTRIBUTION A: Approved for public release; distribution is unlimited. 13

14. BNNT Multifunctionality
Carbon Boron nitride
nanotubes nanotubes
Mechanical
Properties 1.33 TPa 1.18 TPa
Electrical Metallic or Semiconducting
Properties semiconducting (~ 5.5 eV band
BNNT gap)
Permanent
Polarity No net dipole dipole
Piezoelectric
(0.25-0.4 C/m2)
Neutron C = 0.0035 B = 767 (B10
Scattering ~3800)
cross-section N = 1.9
Thermal Stable to Stable to
CNT
Oxidative 300 – 400 C in 800 C in air
Stability air
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15. Single Tube Nanomechanics
Tensile Test 1st report of radial deformability of BNNT
Effective Radial Elastic Modulus (GPa)
single-wall Boron Nitride Nanotube
60 Carbon Nanotube
double-wall
40
Single tube pull-out test triple-wall
Dr. Changhong Ke
2010 AFOSR
Young
20
Investigator
Award
0
Peel Test 0 1 2 3 4 5 6
Nanotube Outer Diameter (nm)
BNNTs have 40-60% lower effective radial
elastic modulus than comparable CNTs
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16. Multifunctionality
Load-bearing + Actuation
1st experimental observation of
electrostrictive strain in BNNT
Theoretical Prediction of SWCNT film
Net Polarization
electrodes
BNNT Dr. Cheol Park
active layer
0.0005
In-Plane Strain (mm/mm)
PE+ES Strain
PE Strain
0.0004 ES Strain
Prof. Alex Zettl
In-Plane Strain (mm/mm)
0.0003
0.0002 Fellow - APS
0.0001
Field induced strain (e33) 0.0000
e33 = d33·E + M33·E2 + … -1.0 -0.5 0.0
Electric Field (MV/m)
Electric Field
0.5
(MV/m)
1.0
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17. Multifunctionality
Load-bearing + Radiation Shielding
Neutron Shielding UV Shielding
2.0
30 wt% (Projected)
1.8
Absorption Coefficient (m) [mm ]
1.6
-1
(Shielding Effectiveness)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
LDPE
30 wt% BN Powder
5 wt% BNNT
LDPE h-BN BNNT
Shielding Effectiveness of BNNT exceeds h-BN on weight basis
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18. Nanostructured Carbon
3D
2D
?
1D Graphene
Carbon
Nanotubes
0D
Fullerene
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19. MURI 11 Topic: Nanofabrication of
3D Nanotube Architectures
Objective: Controlled assembly and atomic-scale bonding of nanoscale elements (e.g. carbon
nanotubes and graphene), leading to network structures with exceptional 3D thermo-electro-
mechanical properties
Materials Enabling Future Aerospace Needs
Multi-Path Synthesis and Assembly
- doping-induced branching
- metal nanoparticle-induced branching
- atomic nanotube welders Multifunctional
Structural
Materials Thermal
Multiscale Characterization Energy
Management
Conversion &
- atomic scale structure Storage
Materials
- node integrity
- mechanical properties
- electron & phonon transport
Multiscale-Multiphysics Design
Morphing & Electronic &
- density function theory Actuation Sensor Devices
- molecular dynamics (MD) Devices
- mesoscale/continuum models
- finite element
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20. Synthesis and Characterization of 3D Carbon
Nanotube Solid Networks, Rice U. MURI Team
Pulickel M. Ajayan, PI Ray Baughman
Synthesis, characterization, Synthesis, fiber spinning,
mechanical, electrochemical, mechanical, thermo-mechanical,
thermal properties electro-mechanical properties
Mauricio Terrones
James Tour Synthesis, chemical processing,
Synthesis, chemistry, atomic scale characterization,
devices, electrical properties structure modeling
Jonghwan Suhr
Matteo Pasquali Synthesis, modeling,
Solvent processing, rheology, thermo-mechanical behavior,
fibers, mechanical properties viscoelastic properties,
composites
Boris Yakobson Multidisciplinary, Collaborative Team
Ab-initio modeling, simulations,
structure-property correlations,
thermo-mechanical properties
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21. Nanofabrication of 3D Nanotube Architectures
Case Western Reserve U., MURI Team
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23. Hybrid Materials Design
Design the structure
based on limitations of
the material
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24. Hybrid Materials Design
Materials Modeling Hierarchy
Macro
Engineering
Materials Science
Micro
Discipline
Chemistry
Atomistic
Physics
Electronic
pm nm µm mm
Length Scale
*Slide created by Dr. Tim Brietzman, ARFL/RXBC
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25. Hybrid Materials Design
Connecting Atomistic & Microscale Behaviors
-- Essential for Materials Design
Stress History
6
Stress (GPa)
5
4
3
Dr. Tim Breitzman
2 AFRL/RXBC
1
Polymer
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 network
Strain
breakdown
6
Number of scissions
4
2 Dr. Rajiv Berry
0 AFRL/RXBN
0 500 1000
Step
Molecular representation of
epoxy resin and mapping of
nanoscale voids due to bond Dr. Jim Moller
scission
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26. ICMSE Hybrid Materials Design
Prof. Reinhold
Dauskardt
Fellow – ACerS, ASM
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27. 2011 Basic Research Initiative
AFOSR/NSF Joint Research Solicitation
ODISSEI: Origami Design for Integration of
Self-assembling Systems for Engineering Innovation
Advance understanding of folding and unfolding of materials
structures across scales for design of engineered systems
• Packaging/Deploying Control Surfaces
Satellites
Solar sails • Materials
Precision air drop Hierarchial materials design
Tube launched systems Atomistic assembly
Active/tunable materials
• Mechanisms
Compliant mechanisms
Actuators
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28. Research Community Leadership
AFRL DOD COMMUNITY
DIRECTORATES
Reliance 21 Board
RX, RV, RW Materials and
AFOSR LRIRs, STTRs, Processing COI
MURIs,
Low Workshops, OTHER AGENCIES
Reviews, Visits
Density Lightweight
Structures
Materials INTERNATIONAL
US-India Tunable Nanostructured
Materials
Materials Forum
US-AFRICA Origami
Initiative Engineering
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29. Acknowledgements
Dr. Marilyn Minus Dr. Ajit Roy Dr. Brandon Arritt
Dr. Greg Odegard Dr. Kishore Dr. Samit Roy AFRL/RV
AFRL/RX
Pochiaju
Dr. Rajesh Naik Dr. Ryan Justice
Dr. Ashlie Martini Dr. Satish Kumar
Dr. James Seferis AFRL/RX AFRL/RX
GloCal Network Corp.
Dr. Robert Moon Dr. Henry
Sodano
Dr. Olesya Zhupanska
2011 DARPA Young Faculty Dr. Chris Muratore Dr. Benji Marayama
Dr. Jeff Youngblood AFRL/RX AFRL/RX
Dr. Sharmila
Mukhopadhyay
Dr. Soumya Patnaik
Dr. Markus J.
Dr. Mesfin Tsige AFRL/RX
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