cellulose nanocrystal characterization by afm · 2009-07-29 · cellulose nanocrystal...
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Cellulose Nanocrystal Cellulose Nanocrystal Characterization by AFMCharacterization by AFM
RoyaRoya LahijiLahiji Post Doc @NINTPost Doc @NINTX. X. XuXu Mechanical EngMechanical EngRyan WagnerRyan Wagner Mechanical EngMechanical Eng
Arvind RamanArvind Raman Prof. Mechanical EngProf. Mechanical EngRon ReifenbergerRon Reifenberger Prof. PhysicsProf. Physics
Robert MoonRobert Moon Forest Products LabForest Products LabPurduePurdue-- Materials EngMaterials EngBirck Nanotechnology CenterBirck Nanotechnology Center
2009 2009 IntnIntn’’ll Conf. on Nanotechnology for the Forest Products Industry, Conf. on Nanotechnology for the Forest Products Industry, June 24June 24--26, 2009, Edmonton, Alberta, Canada26, 2009, Edmonton, Alberta, Canada
OutlineOutline
MotivationMotivationAtomic Force Microscopy (AFM)Atomic Force Microscopy (AFM)ResultsResultsSummarySummary
Crystalline
Disordered
Aci
d H
ydro
lysi
s
Cellulose Nanocrystals (CNCs)Cellulose Nanocrystals (CNCs)
Wood cellulose nanocrystals, Wood cellulose nanocrystals, LiaLia StanciuStanciu
Cellulose NanocrystalsCellulose Nanocrystals
BeckBeck--CandanedoCandanedo et al., et al., BiomacromoleculesBiomacromolecules, 2005, 6, 1048, 2005, 6, 1048
CNC Source Length Cross-Section Algal >1000nm 10-20nm
Bacterial 100 to >1000nm 5-10nm by 30-50nm
Cotton 200-350nm 5nm
Tunicate 100 to >1000nm 10-20nm
Wood 100-300nm 3-5nm
CottonCotton TunicateTunicate WoodWood
400nm
Cellulose NanocrystalsCellulose NanocrystalsPropertiesProperties
Cellulose NanocrystalsCellulose NanocrystalsPropertiesProperties
Encouraging Reinforcement Material
CNC Functional UnitCNC Functional Unit““uniformuniform”” building block building block High Aspect ratioHigh Aspect ratio““GoodGood”” Mechanical propertiesMechanical properties““ReactiveReactive”” surfacesurface
Ideal Ideal GREENGREEN NanoparticleNanoparticle
Function
AvailabilityAvailabilitySustainabilitySustainabilityBiodegradableBiodegradableNonNon--petroleum Basedpetroleum BasedRenewableRenewableCarbon NeutralCarbon NeutralCarbon SequesteringCarbon SequesteringLow Health RiskLow Health Risk
EnvironmentEnvironmentAnimalAnimal
Green
Source: Ikkala, 2004.
CNC CompositesCNC Composites
Composite PropertiesComposite PropertiesThermal StabilityThermal StabilityElastic ModulusElastic ModulusElongationElongationTensile StrengthTensile Strength
CNCCNC--Matrix InterfaceMatrix InterfacePercolation ThresholdPercolation Threshold
L. Oksman, Wood fiber 2007 conference
T. Zimmermann, Wood fiber 2007 conference
Not Reaching Full PotentialCNCs
No CNCs
Percolation ThresholdPercolation Threshold
( )m
f
f
fE
VEVcE −+
= 11 ( ) mfffc EVEVE −+= 1
E
Volume Fraction Fiber
E1
E2
Capadona et al., Science, 2008.
0 1
Transverse Load Transfer
Motivation: CNC CharacterizationMotivation: CNC Characterization
Not much known about CNCsNot much known about CNCsCharacterize Characterize ““building blockbuilding block””
Surface ChemistrySurface ChemistryMechanical PropertiesMechanical PropertiesWater Interaction Water Interaction UniformityUniformityCNC MorphologyCNC Morphology
Insight for Composite Processing & PropertiesInsight for Composite Processing & PropertiesLoad Transfer across Transverse SurfacesLoad Transfer across Transverse Surfaces
CNCCNC--Matrix InterfaceMatrix InterfaceCNCCNC--CNC InterfaceCNC Interface
Necessary for Predictive ModelingNecessary for Predictive Modeling
Modulus of ElasticityModulus of ElasticityBased on Idealized Cellulose Based on Idealized Cellulose IIββ SimulationsSimulations
No Transverse Elasticity
Developing Characterization ProtocolsDeveloping Characterization ProtocolsWhere we are atWhere we are at…….. ……where we need to be!where we need to be!
Approach: Approach: AFM TechniquesAFM TechniquesContinuum ModelingContinuum ModelingMolecular Dynamic ModelingMolecular Dynamic Modeling
Stone AgeF 1
ObjectivesObjectivesDevelop CNC Measurement CapabilitiesDevelop CNC Measurement CapabilitiesAssess Uniformity of CNCsAssess Uniformity of CNCs
Surface ChemistrySurface ChemistryMechanical PropertiesMechanical Properties
InIn--situ with Changes in Relative Humiditysitu with Changes in Relative Humidity
Scanning Probe Microscopy (SPM)Scanning Probe Microscopy (SPM)TipTip--Surface Interactions: Surface Interactions:
Physical contactPhysical contact Electrostatic forceElectrostatic forceLateral forceLateral force CapacitanceCapacitancevan van derder Walls interactionsWalls interactions ThermalThermalMagnetic forceMagnetic force
Ernst-Moritz-Arndt-University, Greifswald
Xintek
Tips Radius Tips Radius ~10nm (typical)~10nm (typical)~2nm (ultra sharp) ~2nm (ultra sharp)
a) contact b) non-contact, small amplitude
c) intermittent contact, large amplitude
d) jumping
a) contact b) non-contact, small amplitude
c) intermittent contact, large amplitude
d) jumping
Imaging Modes Imaging Modes Contact Contact Vibrating (non & intermittent contact)Vibrating (non & intermittent contact)JumpJumpImaging under Gas or LiquidImaging under Gas or LiquidTip Chemical FunctionalizationTip Chemical Functionalization
Atomic Force Microscopy (AFM)Atomic Force Microscopy (AFM)
TopographyTopographyStiffnessStiffnessPullPull--off forceoff force
AFMAFM--PurduePurdueNanotech AFMNanotech AFM
Si tips, 10nm tip radiusSi tips, 10nm tip radiusStiffness 0.65 N/m Stiffness 0.65 N/m (manufacturer)(manufacturer)
measure each tipmeasure each tip0.90.9--2.5N/m2.5N/m
Resonance Frequency: ~40KHzResonance Frequency: ~40KHzAtmosphere ControlAtmosphere Control
30% & 0.1% RH30% & 0.1% RH
Sharp AFM tips Sharp AFM tips (<10nm)(<10nm)Consistent tip shapeConsistent tip shapeDurableDurableLess expensiveLess expensiveImage & Property MeasurementImage & Property Measurement
AFM TipsAFM TipsSharp Sharp (<10nm)(<10nm)
Good
Ultra Sharp Ultra Sharp (<2nm)(<2nm)Inconsistent tip shapeInconsistent tip shapeFragileFragileExpensiveExpensive
Bad
10 nm
CNC: ~4CNC: ~4--10nm10nm
Mica
ArtifactsArtifactsChanging contact curvatureChanging contact curvatureEdge effectsEdge effectsAFM Tip dilationAFM Tip dilationAFM Tip bluntingAFM Tip bluntingAFM TipAFM Tip--toto--Tip changesTip changesMeniscus FormationMeniscus Formation
Idealized TipIdealized Tip--CNC Contact Geometry CNC Contact Geometry
AFM Tip
AFM: ForceAFM: Force--DisplacementDisplacement
A
BC
DE
A
B
C
D E
F
G
H
F
G
H ApproachWithdraw
AFM: ForceAFM: Force--DisplacementDisplacement
IIII -- PullPull--off Force off Force TipTip--Surface InteractionSurface InteractionAdhesionAdhesionCNCCNC--surface Chemistry?surface Chemistry?
II --Slope Slope CantileverCantilever--CNC stiffnessCNC stiffnessElastic ResponseElastic ResponseCNCCNC--Modulus?Modulus?
II
II
ApproachWithdraw
Force DisplacementForce Displacement
90nm
Topography
Data CollectedData CollectedTopography, PullTopography, Pull--off, Stiffnessoff, Stiffness128 x 128 points128 x 128 pointsResolution based on mapping areaResolution based on mapping area
Maps Maps TopographyTopographyStiffnessStiffnessPullPull--off Forceoff Force
~2wt% CNC suspension 400nm
Deposit ~10 μl of solution on to freshly cleaved mica sheet
DI wash
Sample PreparationSample Preparation
TopographyTopography
Observations Observations Variable heightVariable height
RH influence?RH influence?not likelynot likelyScanScan--toto--scan ~1nm scan ~1nm not not ““exactlyexactly”” same tracesame trace
0.1% RH0.1% RH
012345678
0 20 40 60 80 100 120 140 160 180 200
Distance (nm)
Hei
ght (
nm) 0.1% RH
012345678
0 20 40 60 80 100 120 140 160 180 200
Distance (nm)
Hei
ght (
nm)
30% RH
0.1% RH
40nm
0.1% RH
×
40nm
0.1% RH
40nm
0.1% RH
×
30% RH30% RH
40nm
30% RH
×
40nm
30% RH
40nm
30% RH
×
×mica CNC
StiffnessStiffness
1.4
1.5
1.6
1.7
1.8
1.9
2.0
0 20 40 60 80 100 120 140 160 180 200
Distance (nm)
Effe
ctiv
e St
iffne
ss (N
/m)
30% RH
0.1% RH
mica CNC
43nm
0.1% RH
43nm
30% RH
× ×
××
1.4
1.5
1.6
1.7
1.8
1.9
2.0
0 20 40 60 80 100 120 140 160 180 200
Distance (nm)
Effe
ctiv
e St
iffne
ss (N
/m)
30% RH
0.1% RH
30% RH
0.1% RH
mica CNC
43nm
0.1% RH
43nm
30% RH
× ×
43nm
0.1% RH
43nm
30% RH
× ×
××
Observations Observations Uniform along lengthUniform along lengthEdge effectsEdge effectsNo CNC height effectsNo CNC height effects
RH RH StiffnessStiffnessMica & CNCMica & CNCMeniscus InfluenceMeniscus Influence
30% RH30% RH 0.1% RH0.1% RH
Force Displacement Force Displacement MOEMOEFo
rce
Distance
Cantilever B
ending
d
Nano Crystal
Approach
Tip Contact
Stiffness PlotsStiffness PlotsRemove Cantilever ContRemove Cantilever Contd several locations d several locations
d ~ Indentation Depth
Mechanical Properties: Wood CNCsMechanical Properties: Wood CNCs
“AFM TIP”
Cellulose
RH=0.1% RH=0.1%
Transverse Modulus Transverse Modulus E=18E=18--50 50 GPaGPa, , Mean: 35 Mean: 35 GPaGPaMedian: 39.5 Median: 39.5 GPaGPa Reasonable, but how accurate?
Forc
e (n
N)
Forc
e (n
N)
Forc
e (n
N)
Forc
e (n
N)
Forc
e (n
N)
Indentation (nm) Indentation (nm)
Indentation (nm) Indentation (nm) Indentation (nm)
Modulus of ElasticityModulus of ElasticityBased on Idealized Cellulose Based on Idealized Cellulose IIββ SimulationsSimulations
Within Range
Mechanical Properties: Tunicate CNCsMechanical Properties: Tunicate CNCs
“AFM TIP”
Cellulose
Hertz ModelHertz Model Continuum ModelContinuum Model Molecular DynamicMolecular Dynamic
Extracting Elasticity:Extracting Elasticity:
Idealized Crystals:Idealized Crystals:
2/3CdF =
Mechanical Properties: Tunicate CNCsMechanical Properties: Tunicate CNCs
806040200
1.41.31.21.1
1
Z[nm]
Nor
mal
forc
e[V
]30 nm
mica
CNC
-0.5 0 0.5 1 1.50
10
20
30
40
50
d (nm)
F (n
N)
Force Indentation Curve
fd cnck*a*(x+b)1.52/3)( bdakL +
0 0.2 0.4 0.6 0.8 10
1
2
3
4R2 Values of Fits
coun
t
R2
Transverse Modulus Transverse Modulus 30 Points along line 30 Points along line HertzHertzMean: 13 Mean: 13 GPaGPa ±± 9 9 GPaGPa (3 STD)(3 STD)
Mechanical Properties: Tunicate CNCsMechanical Properties: Tunicate CNCs
Mechanical Properties: Tunicate CNCsMechanical Properties: Tunicate CNCs
Transverse Modulus Transverse Modulus 100 Points along line 100 Points along line HertzHertzMean: 3 Mean: 3 GPaGPa ±± 5 5 GPaGPa (3 STD)(3 STD)
51nm 706050403020100
10
8
6
4
2
0
X[nm]Z[
nm]
Analysis of Transverse FZ curves
0 0.005 0.01 0.015 0.02 0.0250
0.05
0.1
0.15
0.2
0.25
Doffset (V)
F (V
)
Force Indentation Curve Comparison of Mica vs. Mica FZ curve
9080706050403020100
2
1.5
1
0.5
0
X[nm]Z[
nm]
51nm 302520151050
0.8
0.75
0.7
0.65
0.6
0.55
0.5
0.45
0.4
Z[nm]
Nor
mal
forc
e[V
]-0.01 0 0.01 0.02 0.030
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Doffset (V)
F (V
)
Force Indentation Curve
9080706050403020100
1.4
1.2
1
0.8
0.6
0.4
0.2
0
X[nm]
Z[nm
]
302520151050
0.8
0.75
0.7
0.65
0.6
0.55
0.5
Z[nm]
Nor
mal
forc
e[V
]
51nm
0 0.01 0.02 0.03 0.040
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Doffset (V)
F (V
)
Force Indentation Curve
9080706050403020100
1.5
1
0.5
0
X[nm]Z[
nm]
51nm 302520151050
0.8
0.75
0.7
0.65
0.6
0.55
0.5
Z[nm]
Nor
mal
forc
e[V
]0 0.5 1 1.5 2
0
5
10
15
20
D (nm)
F (n
N)
Force Indentation Curve
fd cncC*k*a*(x+b)1.5
0 0.2 0.4 0.6 0.8 10
1
2
3
4
5
6R2 Values of Fits
coun
t
R2
51nm 80706050403020100
2.5
2
1.5
1
0.5
0
X[nm]Z[
nm]
302520151050
0.75
0.7
0.65
0.6
0.55
0.5
0.45
Z[nm]
Nor
mal
forc
e[V
]0 0.5 1 1.5
0
5
10
15
D (nm)
F (n
N)
Force Indentation Curve
fd cncC*k*a*(x+b)1.5
0 0.2 0.4 0.6 0.8 10
1
2
3
4
5
6R2 Values of Fits
coun
t
R2
51nm 80706050403020100
1.4
1.2
1
0.8
0.6
0.4
0.2
0
X[nm]
Z[nm
]
302520151050
0.75
0.7
0.65
0.6
0.55
0.5
0.45
Z[nm]
Nor
mal
forc
e[V
]0 0.5 1 1.5
0
5
10
15
D (nm)
F (n
N)
Force Indentation Curve
fd cncC*k*a*(x+b)1.5
0 0.2 0.4 0.6 0.8 10
0.5
1
1.5
2
2.5
3R2 Values of Fits
coun
t
R2
51nm 80706050403020100
1.2
1
0.8
0.6
0.4
0.2
0
X[nm]Z[
nm]
302520151050
0.75
0.7
0.65
0.6
0.55
0.5
0.45
0.4
Z[nm]
Nor
mal
forc
e[V
]0 0.5 1 1.5
-5
0
5
10
15
D (nm)
F (n
N)
Force Indentation Curve
fd cncC*k*a*(x+b)1.5
0 0.2 0.4 0.6 0.8 10
1
2
3
4R2 Values of Fits
coun
t
R2
51nm 706050403020100
10
8
6
4
2
0
X[nm]
Z[Å
]
302520151050
0.75
0.7
0.65
0.6
0.55
0.5
0.45
0.4
Z[nm]
Nor
mal
forc
e[V
]0 0.2 0.4 0.6 0.8 1
-5
0
5
10
15
D (nm)
F (n
N)
Force Indentation Curve
fd cncC*k*a*(x+b)1.5
0 0.2 0.4 0.6 0.8 10
1
2
3
4
5R2 Values of Fits
coun
t
R2
Summary Summary Key ObservationsKey Observations
Variable CNC Height ProfileVariable CNC Height ProfileUniform StiffnessUniform StiffnessInfluence of RH on measurementsInfluence of RH on measurements
Elastic Modulus EstimatesElastic Modulus EstimatesComplimentary Experimental & Modeling Complimentary Experimental & Modeling QualitativeQualitative
Wood: 18Wood: 18--50GPa (FEM)50GPa (FEM)Tunicate: 0Tunicate: 0--22 22 GPaGPa (Hertz)(Hertz)
Artifacts need to be accounted forArtifacts need to be accounted for……
AcknowledgementsAcknowledgements
Forest Product Laboratory:Jim Beecher, Chris Hunt, Rick Reiner, Allan Rudie, Ron Sabo
Funding: Cooperative Agreement with Purdue Funding: Cooperative Agreement with Purdue
Funding: Seed Grant Funding: Seed Grant
Thank YouThank You
Questions ?