Dale W' Schaefer, Jian Zhao

1
Hierarchical Structure of Carbon Nanotubes and
Nanofibers
Dale W. Schaefer, Jian Zhao Department of
Materials Science and Engineering University of
Cincinnati Cincinnati, OH 45221-0012 Janis
Brown, Dave Anderson, Max Alexander, Liz
Donaldson, Lindsay Richardson and Jeff Baur Air
Force Research Laboratory Dayton, Ohio Jan
Ilavsky National Institutes of Standards and
Technology UNICAT Advanced Photon Source Argonne
National Laboratory, 9700 South Cass
Avenue Argonne, IL 60439
Dynamic Mechanical Properties
Stress-Strain Data SWNT/PU
Strain Softening
Multi-walled Nanofibers Single-walled
Nanotubes
MWNF
SWNT
ASI Nanofibers
Light
Light USAXSSAXS
TEM comparing MWNFs (left) and SWNTs (right).
Note the branched polymer character of the SWNTs.
The SWNTs are clustered into ropes that are not
disrupted upon water suspension. Images are from
Air Force Research Laboratory (AFRL).
Surface roughness?
Loading Dependence (MWNTs in PU)
Scattering from Nanotubes
Large-Scale Structure of Suspended SWNTs and MWNFs
Align
De network
SWNT Fractal Structure
MWNF Rod-like Structure
Loss
Modulus
Nanofiber -Polyelectrolyte Dispersion in PU
Dispersion Strategies Polyelectrolyte coatings
Nanafibers dispersion
Comparison of Small-angle Light scattering from
nanotubes and nanofibers.Dispersing agents of
PMAA, PSSO3 and PAAHCl were used to assist
dispersion in water.
Short-Scale Structure (dried suspension)
SWNT Aggregates are Very Robust
Sonication has little effect on Large Scale
Structure of SWNTs
Polyelectrolyte-Modified Particles
Hard Particle Diameter 2.4 x RG 4.3 nm 43
Å Too small?
Generic Colloid
As Received (dirty)
Nanoparticle/polyurethane composite film
Mechanical Properties of Coated Nanofiber/PU
Composites
Comparison of DMA data from uncoated, one layer
and two layers coated 15wt nanotubes PU films.
The loss as Tan delta (lower three curves) is
plotted on the right axis. The legend in the
figure indicates the strain sweep sequence.
These samples were all swept three times.
Reciprocal space data on SWNTs dispersed in water
with polystyrene sulfonate and polymethylacrylic
acid.. The data is from a Micromeritics
Digisizer.
Acknowledgements The UNICAT facility at the
Advanced Photon Source (APS) is supported by the
Univ of Illinois at Urbana-Champaign, Materials
Research Laboratory (U.S. DOE, the State of
Illinois-IBHE-HECA, and the NSF), the Oak Ridge
National Laboratory (U.S. DOE under contract with
UT-Battelle LLC), the National Institute of
Standards and Technology (U.S. Department of
Commerce) and UOP LLC. The APS is supported by
the U.S. DOE, Basic Energy Sciences, Office of
Science under contract No. W-31-109-ENG-38.