What Else Might You Do With
Nanofibrillar Cellulose Besides
Make Nanocomposites?
William T. Winter
SUNY-ESF
Syracuse, NY 13210
http://www.esf.edu/cellulose
Overview
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What does nature do?
Chemical modifications
Biomaterials
Control of physical properties
Filtration
Sensors
Conduction / Stimuli responsive cellulose
Materials that maintain the cellulose
layered assembly / morphology
• Conclusions
Rebar Mimics Nature
Lobster
Exo
skeleton
D. Raabe et al. (2005)
Acta Materialia 53:
4281–4292
Cellulose Morphology
Fiber (cell)
White pine tracheids
Wood Cell
Schematic
ESF archives
Cote’ - ESF
Microfibril
Hanna, ESF
Cactus Spines
• Cactus spines are
made of cellulose in
a flexible arabinose
polymer matrix.
• Birds use the spines
as tools to extract
insects
• Some tribes have
used them as
needles
Chemical Modification Choices
• Esters / Ethers
• Oxidation -
– C(6) carboxylation,
charge
• -CH2OH > -CH2NH2 (or 3+)
– Attach proteins,
nucleic acids,
– Charge surface
(oligo or polyaniline)
Specific Surface Areas
from Uptake of Congo Red
3
2
7
0
4
1
6
6
7
8
8
Goodrich & Winter (2006) Biomacromol, submitted
Tissue Scaffolding /
Biomedical Devices
• Scaffolding – route to regenerating
bone, skin, other tissues
• Devices / Materials – stents, bone
cements
This is what you have to match:
Freeze Dried Bacterial Cellulose
A) Compact Surface
B) Open Surface
Free of lignin, pectin, hemis etc
G.Helenius, H. Bäckdahl, A. Bodin, U. Nannmark, P.
Gatenholm, and B. Risberg (2006) Journal of
Biomedical Materials Research, 76A (2): 431-8
BC is not rejected in rat
tissue
Cellulose Binding Domains: A key
to immobilized proteins on
cellulose
• Since CBD
binds very
tightly to
cellulose,
these could
create
largely
permanent
proteinated
surfaces
Pinto et al (2006)
Cellulose on-line
Reinforcement in Optically
Transparent Materials
• Up to 70% cellulose in acrylate -highly
transparent,
• a low thermal expansion coefficient comparable to
silicon crystal,
• Mechanical strength is five times that of
engineered plastics.
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M. Nogia, K. Handa, A. Norio Nakagaito, Hiroyuki Yano, Applied Physics
Letters (2005), 87(24), 243110
Nanoporous Filtration for DNA
elerctrophoretic separation on a
microchip
0.49%HPMC; 0.3% BC +0.49%HPMC
M. Tabuchi and Y. Baba (2005) Anal. Chem 77:7090
Sensor Assembly on CA Nanofibers
Dip coat
+ Eu+3
Electrospun
CA 1 μm bar
X. Wang et al. (2004) Nanoletters 4(2):331
Sensitivity to cyt. C
(fluorescence)
Routes to conduction
• Soaking a nanofiber
array in MWCNT
with surfactant
• Achieved 0.14 S/cm
• (Cu ~ 600 kS/cm)
Stimuli sensitive
effects
• The celluloses here
are actually
microscale
• Other work shows
that in other
systems the
effects increase
with smaller
particles.
• Electrorheological
elastomers too
Zhang, Winter & Stipanovic (2005) Cellulose 12:135
Synthesis of SiC Ceramics by the
Carbothermal Reduction of Mineralized
Wood with Silica
Y.S. Shin etal (2006) Advan. Mat. 17:73
X-section
Pit w. fibers
Pine> SiC
Radial s.
Deignify w.
HCl
1400C
+Si@ 700C>
SiC porous
replicas
Poplar>
SiC
Forming Crystalline Silicon
Carbide
Wood structured SiC stable to 1400 ºC
SA ~ 60 – 100 m2/g
Useful for gas adsorption / separation at high T
Conclusions/ Future Work
• Think of the cellulose nanoparticles as starting
points not an end in themselves
• Keeping the cellular/microfibrillar organization can
lead to useful inorganic materials
• We need to make wood cellulose as pure as
bacterial cellulose for medical applications
• Acid hydrolysis may not be the best route and
perhaps we should think of these particles as
coproducts
• Ultimately economics will dictate which products
survive and mature
Any Burning
Questions?