yetter-nano engineered energetic materials durint-muri review
TRANSCRIPT
2004 ARMY ENERGETIC MATERIALS MURI AND DURINT REVIEW MEETING
Picatinny Arsenal Officers’ Club27-28 October 2004
NANO ENGINEERED ENERGETIC MATERIALS
(NEEM) MURIOverview
Richard A. YetterThe Pennsylvania State University
andthe NEEM MURI Team
Issues and Motivation
• Potential benefits of nano energetic materials:More powerful. Controlled rate of energy release. More reliable. Higher density. More reproducible. Reduced sensitivity. Reduced vulnerability. Increased storage lifetime. Safer to handle. Multi-functionality.
• Modest gains to date: While some performance improvement has been demonstrated, the full extent of the anticipated gains fromnanoscale energetic materials has not been realized in large part due to the incompatibility of length scales.
Objectives
• Develop new methodologies to assemblenano-energetic materials that provide concurrent increases in performance and managed energy release rate while reducing sensitivity.
• Obtain fundamental understanding of the relationship between the design of nano-engineered energetic materials and their reactive and mechanical behaviors.
Critical Technology Issues
• Self-assembly and supramolecular chemistry of the fuel and oxidizer elements of energetic materials have lagged far behind chemistries in other disciplines (e.g., microelectronics, biological systems, and pharmaceuticals).
• There is no fundamental understanding of what type of supramolecular structures provide desirable performance in combustion, mechanical, and hazard characteristics.
Design Possibilities
polymer binder
nano-metallicparticle
micron-crystallineoxidizer
nano-crystallineoxidizer
nano-energetic materials
nano Al & Bnano RDX, HMX, & ADN
carbon nanotubes
self-assembledmicron-to-millimeter scale
energetic structure
self-assembledenergetic material
with gradient in chemical composition
conventionally assembledenergetic material with
micron-to-millimeter scale energetic structures
Program Philosophy
• Bring together leaders in nanotechnology and propellants and explosives
• Couple multiscale modeling and multiscalediagnostics
• Research and develop new concepts for assembling and understanding the dynamics of nano engineered energetic materials
Participating MURI Team Members
• David Allara, PSU: chemistry, nanotechnology, self-assembly• Ralph Nuzzo, UIUC: chemistry, nanotechnology, self-assembly• Dana Dlott, UIUC: chemistry, energetic materials, ultrafast laser
spectroscopy• Priya Vashishta, USC: physics, materials, atomistic modeling• Rajiv Kalia, USC: physics, materials, multiscale modeling • Aiichiro Nakano, USC: physics, materials, multiscale modeling • Vigor Yang, PSU: engineering, energetic materials, combustion
modeling• Richard Yetter, PSU: engineering, energetic materials,
combustion diagnostics• Kenneth Kuo, PSU: engineering, energetic materials,
combustion and ballistics
Program Elements
• Synthesis and Assembly• Theoretical Analysis and Design• Experimental Characterization
Program Structure and Interactions
Synthesis & Assembly
Theoretical Experimental NEEM
nano
- mac
ro
PSUUIUC
Modeling &Simulation
Characteriz
macro
-na
nonano -USC
PSU
ation & Diagnostics
macro
UIUCPSU
Synthesis, Self-Assembly, andSupramolecular Chemistry of Nano-
Structured Energetic Materials
Significant Research Experience on Al Synthesis, Fabrication, and Surface Chemistry
Nuzzo – UIUC, Allara - PSU
• SAMs on Al(native oxide)/Al• Al(metal)-SAM Structures & Interactions• Al Vapor Deposition Processes• Al Surface Chemistry• Materials Characterization
Nano Scale Energetic Materials Synthesis and Passivation: Nuzzo-UIUC & Allara-PSU
H Si H
H
Si
3/2 H2
TMA +
3/2 H2
AlH3-TMA
H Si H
H
H Si H
H
Si
3/2 H2
TMA +
3/2 H2
AlH3-TMA
• High surface area aluminum nanoparticles would be ideal high-energy materials
• A few examples of small aluminum clusters have recently been described (reductive syntheses), but there are no investigations of their use as high energy materials
• The Al nanoparticles consist of metallic aluminum cores surrounded by a monolayer of a protective shell
• 10 and 100 aluminum atoms and particle diameters between 0.5 and 1.3 nm
Generalize and Expand Synthetic Approaches
Stabilized nano-clusters via metal ligand interactions
Potential route to capped Al nanocluster
Develop new synthetic methodologies for affecting the low temperature synthesis of highly reactive nanoclusters
Aluminum cluster (far right) consists of nested shells containing (from left to right) 13, 44, and 20 aluminum atoms
A. Ecker, E. Weckert, and H. Schnöckel Nature 1997, 387, 379.
AlI + LiN(SiMe3)2 →Al77[N(SiMe3)2]202-
Nano Scale Energetic Materials Synthesis and Passivation: Nuzzo-UIUC & Allara-PSU
Generalize and Expand Synthetic Approaches to Aluminum Clusters with Sizes Ranging to 100 nm
• New SAMs for Cluster Passivation and Size Control•Thermal Cluster Growth
• Ligand-Directed Association• Directed Synthesis
•Full Characterization/Understanding of Structure and Properties at all Length Scales
High Energy Content Nanocomposites: Nuzzo-UIUC
• Novel Growth Chemistries
• Composites from Aerosol and Particle Spray Deposition Processes, e.g., Nanoparticle Metal/Fluorocarbon Composites
Teflon telomerparticles
Swollenparticles
Al growthvia infusion
Encapsulation by vitrification
Dispersible to ~0.2 µm Particles
PFK/PFE
Thermal Spray Deposition(e.g. TMAA / TiCl4 / MP 1100)
Zonyl® MP 1100
• Sub �m Teflon particles swollen in solvent,
• Al nanoparticles grown & passivated in pores,
• Spherical particles packed to form lattice ofpassivated nanoparticles
Nano Structured Energetic Materials-Model Systems Nuzzo-UIUC
Develop strategies for manipulating the larger mesoscopic organization of high energy nanoscale materials by directed design
Fabrication of Energetic Structures Using a Soft Lithographic Patterning Technique
10µm
Master
Spin-CastPFSOx
UVO
AdhesiveContact
DecalTransfer
Sputter DepositAluminumx2
Weld TwoAluminum Films
Laminate Decal
Decal Release for 3D Integration
10µm
Master
Spin-CastPFSOx
UVO
AdhesiveContact
DecalTransfer
Sputter DepositAluminumx2
Weld TwoAluminum Films
Laminate Decal
Decal Release for 3D Integration
Bottom layer strong oxidant such as HMX, which is readily deposited in thin film form from the vapor phase
Nano Structured Energetic Materials-Model Systems Nuzzo-UIUC
Fabrication of Energetic Structures Using Decal Transfer Lithography
Si
Si
Si
“Master”
Photoresist pixel post array
Spin coat and cure thin PDMS film.
Remove PDMS membrane stencil mask.
Place PDMS membrane on substrate.
Evaporate layer through membrane.
5-250 �m (dia); 5-150 �m (ht)
3-100 �m (thick)
- Stacked disks of oxidizer, e.g., RDX- Al with 5 mm pitch- Si is a silicon wafer- PDMS is a conformal silicone polymer membrane
-capable of achieving submicron resolution in large pattern area
Effect depositions for sequential levels.
Lift-off membrane to reveal pixel array.
Cap or align second mask for 3D structures
Cap or align second mask for 3D structures
Nano Structured Energetic Materials-Model Systems Allara-PSU
• Thin film nanostacks [ fuel-(oxidizer-fuel)N- ] (~1-3 nm thick)
fuel (Al, etc.)
oxidizer layer (SAM)passivation layertemplate layer
• Interface/Surface characterization – static• Capabilities:
• in-situ (UHV): IR, XPS, ToF-SIMS, AFM• ultrasensitive BET for planar-scale surface/pore areas
• Model structure characterizations:• structures, chemical interactions at interfaces• T dependence of structures (stability, chem degradation)
Shock Precipitation and Supercritical Fluid (SCF) Processing of Nano-sized Oxidizers: Kuo-PSU
• Two solvent-based methods will be examined in this study– Shock precipitation (SP) technique; – Supercritical fluid (SCF) technique.– A combined SP/SCF processing technique will also be considered.
• Oxidizer crystals to be considered include: RDX, ADN (ammoniumdinitramide), HNF and FOX-7 (1,1-diamino-2,2-dinitroethylene).
• Two SCF methods will be investigated for application to energetic materials (w/ Victor Stepanov of ARDEC):– Rapid Expansion of Supercritical Solutions (RESS).– Supercritical Anti-Solvent precipitation (SAS). – Rapid mixing via opposed-jet impinging flows will be applied to increase the
rate of nucleation and thus reduce the particle size while increasing yield.
Theoretical Modeling of Nano-Structured Energetic Materials from the
Atomistic/Molecular Scale to the Macroscale
Coupled FE/MD/QM Simulations Vashishta, Kalia, Nakano - USC
Multiscale QM/MD/FE simulation (top) implemented on a Grid (bottom) of supercomputers, data archive, and virtual environment
Approach:• Finite element (FE)• Atomistic molecular dynamics (MD)• Quantum-mechanical (QM) calculation based on density functional theory (DFT)
Challenge: Seamlessly couple QM scheme & MD approach based on effective interatomic potentials
Collaboratory for Advanced Computing & Simulations (CACS)• 1,512 processor Intel Xeon Linux cluster at USC• 2.4 million processor-hours of computing on IBM SP4 & Compaq AlphaServer at DoD Major Shared Resources Centers
Nano Aluminum Particle OxidationVashishta, Kalia, Nakano - USC
Number of Atoms: ~ 250,000 Al, ~ 550,000 O; Initial Al cluster 100Å radius
Oxidative Percolation
Oxidation Under Closed ConditionsMetal Oxide Core-Shell Structure
No heat dissipation allows rapid T increase in surface and core. Larger spheres correspond to oxygen and smaller spheres to aluminum; color represents the T.
OAl4 clusters percolate to form a neutral shield around Al nanoparticle, which impedes oxidation
Oxide thickness saturates at 40Å after 0.5 ns – good agreement with experiment (Nieh et al., Acta mater. 44, 3781 (1996)
RDX Molecule on Al (111) SurfaceVashishta, Kalia, Nakano - USC
Quantum mechanical MD simulation in the framework of the densityfunctional theory (DFT)
NEEM Behavior in Two-Phase Flow Environments at Meso & Macro Scales : Yang - PSU
Al Particle Diameter (m)
Flam
eSp
eed
(m/s
)
10-6 10-5 10-4
10-2
10-1
100
101
10-2
10-1
100
101
� = 0.8
0
Analytical predictionNumerical predictionExperimental data
• Couple Relevant Processes at Micro and MesoLength Scales to Macroscale Phenomena
• Investigate the transport and combustion of nano-sized particles in reactive flow environments
• Establish general analysis accommodating particle & thermo-fluid dynamics for two-phase flow interactions
• Identify key mechanisms and parameters for maximizing energy release
Aerosol Al - Air Flame
~ 1 cm~ 1 cm 1.9 cm1.9 cm
HeterogeneousSolid Phase
Ts = ~ 700 K
Tmelt = 558 K
Tsf = ~ 2000 K
Tdark zone= ~ 1250 K
PrimaryFlame Zone
(HMX Vapor /Liquid Interface)
(HMX Melt Front)
GAP PolymerResidue
HMX GAP
Dark Zone
SecondaryFlame Zone
HCN, H CO, N O, H , CO2 2
2 2 22
Major Species in Dark Zone:N , H O, NO, CO,
Foam Layer
Rapid Consumption ofHCN and NO
Decomposition, Evaporation, and Gas-Phase Reactions (Bubble)
Combustion-Wave Structure of HMXGAP Pseudo-Propellant
Optimization of NEEM Fabrication Techniques based on Supercritical (SCF) Processing: Yang - PSU
Shadowgraph images for injection of supercritical methane/ethylene fluid into subcritical environments at various conditions xCH4=0.1 and d=1.0 mm.
Pinj/Pc 1.15 1.16Tinj /Tc 1.23 1.03Pinj/Pchm 35.7 36.7� (Cp/Cv) 1.56 5.51
• The Tinj/Tc=1.03 jet has a large jet expansion angle and opaque appearance due to condensation
• Jet expansion angle differences may come from differences in specific heat ratios and the pressure rise due to the release of latent heat during condensation
Numerical Modeling and Optimization of SCF Fabrication Techniques:
• Rapid expansion of supercritical solution (RESS)• Supercritical anti-solvent precipitation (SAS)
Modeling will include:• Important near- and super- critical fluid
phenomena, including transcriticalthermodynamic and transport anomalies
• Parametric studies will examine effects of flow parameters and hardware design attributes on production of nano-sized materials
• Outcome will be improvements to existing techniques and new innovative concepts
Density gradient field
Experimental Characterization of Reactive and Mechanical Behaviors ofNano-Structured Energetic Materials
Time and space resolved spectroscopy ofnanoenergetic materials: Dlott - UIUC
Approach• Picosecond laser flash-heating of nanoenergetic materials
(Picosecond CARS, time-resolved emission, streakscopefor long distance and directional propagation)
• Ultrafast (sub ns) microscopy of laser-initiated materials• Femtosecond IR laser, time resolved IR spectroscopy (C-
H, C-C, Al-O, Al-F, C-F, O-H, etc.)• Femtosecond laser-driven shock compression and shock
spectroscopy of nanoenergetic materials (pressure 5-10 GPa, material velocity ~0.8 km/s, shock velocity ~4 km/s (40Å/ps), compression factor �V = 0.2, rise time 2-3 ps, fall time 15 ps)
High repetition rate laser flash-heating (100/s) Dlott - UIUC
1 mm
oxidizer100 pspulse 100 nm
transparent polymer oxidizer
10 cm10 cm
40 mg sample (3 �m thick). Each shot 50ng (150 �mdiam). 105
shots per sample
100 ps heating pulse ismatched to metal particle thermal conduction.Particle is uniformly heated, surroundings cold
Fast Spectroscopy of Laser Initiated NanoenergeticMaterials: Dlott - UIUC
-1 0 1 2 3 4 50.0
0.2
0.4
0.6
0.8
1.0
delay time (ns)
ON
O2
surv
ival
frac
tion
0.2%0.5%1.0% 2.0%
J = 5.9 J/cm2
abrupt transition
when reactions coalsece~300 ps
conc.indep
-1 0 1 2 3 4 50.0
0.2
0.4
0.6
0.8
1.0
delay time (ns)
ON
O2
surv
ival
frac
tion
0.2%0.5%1.0% 2.0%
J = 5.9 J/cm2
abrupt transition
when reactions coalsece~300 ps
conc.indep
0 10 20 30time (ns)
1% in NC5.6 J/cm2
3.9 J/cm2
1.8 J/cm2
0.4 J/cm22nsseveral
ns
0 10 20 30time (ns)
1% in NC5.6 J/cm2
3.9 J/cm2
1.8 J/cm2
0.4 J/cm22nsseveral
ns
Energy release via time-resolved emission
inte
nsity
(arb
)
Nitrate group consumption in Alex/NC
Energy release ~2 ns at low concentrationSlows down at higher fluence as reaction propagates over greater distances
Surface and Subsurface Analysis of Nano Engineered Energetic Materials: Yetter - PSU
Microscope
MicroscopeObjectiveEpi-Fluorecent
Prism/Filter Cube
BeamExpander
CCD Camera
Energetic Material
Nd:YAG Laser
CO2 Laser Irradiation / Ignition Source/ / Flame Propagation
Microscope
MicroscopeObjective
Epi-FluorecentPrism/Filter Cube
Energetic Material
CO2 Laser Irradiation / Ignition Source / Flame Propagation
Spectrometer
CCD Camera
• In-situ reacting energetic material studies using upright and inverted optical microscopes with high speed photography, micro particle image velocimetry, micro laser induced fluorescence and micro Raman spectrometry
• In-situ studies of reacting energetic materials using environmental scanning electron microscope at surface and subsurface temperatures of bulk material
Examples of Diagnostics Implementation
ESEM
Heating Stage
Sample Crucible
Heated Cell of FEI Quanta 200 SEM for simulating surface processes during reaction
ICCD
Micro Burner for Combustion Analysis of Nano Composites and Nano Metallic - Metallic Oxidizer
Systems: Yetter - PSU
Optical Combustion Chamber– Ignite thermite mixture or pressed
pellet to study effect of pressure, initial temperature, trapped gas effect
– High-speed video records to determine regression rate
– Pyrometer to measure the surface temperature of the condensed phase products
– LIF to measure presence of AlO
High-SpeedCamera
IgniterOptical Combustion
Chamber
ThermiteMixture
Molten Product Container
Pyrometer
High-SpeedCamera
IgniterOptical Combustion
Chamber
ThermiteMixture
Molten Product Container
Pyrometer•Formulate and study the reaction dynamics of nano-composite thermite systems
• Investigate systems that produce significant gas at high-energy release rates
•Determine the effect of composition and physical characteristics of the trapped gas, initial temperature, and pressure on regression rates of mixtures
Formulation and Combustion Analysis of New and Advanced Nano-Energetic Materials and Propellants
Kuo - PSU
• Burning Rate Measurements of Newly Processed Propellants• Burning Surface Observation of Propellants with Nano-Particles• Laser Ignition Characteristics of New propellants with Nanosized
Energetic Particles
Propellant burning at 8,000 psi
Time [ms]:0 140 270 450 630
1 mm
0.1
1
10
100
0.8
1.2
1.6
2
2.4
2.8
3.2
1000 104 105
AME - RDX/BBA/Alex Nano-RDX/BBA/Alex AHE - HNF/RDX/BBA/AL
AHE/AMEAHE/Nano-RDX
Burn
Rat
e
Burning Rate R
atio
Pressure [psig]
Solid Propellant Strand Burner: capabilities/features� Optically accessible� Up to 9,500 psi capability� Temperature control –60oC < T < 80o
Interactions External to MURI TEAM
DoD and DoE Laboratories
Energetic Materials Design
ARO MURI
Synthesis & Assembly
Theoretical Simulation &
Modeling
Experimental Characterization &
Diagnostics
NEEM
Center for NanoEnergetic
MaterialsARO DURINT
Industry
Emails of Team Member
• David Allara, PSU: [email protected]• Ralph Nuzzo, UIUC: [email protected]• Dana Dlott, UIUC: [email protected]• Priya Vashishta, USC: [email protected]• Rajiv Kalia, USC: [email protected]• Aiichiro Nakano, USC: [email protected]• Vigor Yang, PSU: [email protected]• Richard Yetter, PSU: [email protected]• Kenneth Kuo, PSU: [email protected]