Polymer-Reinforced Single Crystals

Polymer-Reinforced Single Crystals:
Formation, Structure, and Properties
Lara A. Estroff
Dept. of Materials Science and Engineering
Cornell University
lae37@cornell.edu
http://laegroup.ccmr.cornell.edu/
Biogenic Polymer Reinforced Single Crystals (PRSCs)
Fractured sea urchin spine
Sea urchin tooth thin section
All of these materials are:
• Calcite (CaCO3)
• Single Crystals
• Composites with
0.02 wt% - 5.3 wt%
incorporated organic
material
Addadi and Weiner, J. Mater Chem, 1998
Robach, et al., J. Struct. Biol. 2005
Prismatic (calcitic) layer from mollusks
Etch 5 minutes acetic acid
Nudelman et al., Faraday Disc., 2007
How do organisms control mineralization?
Shell, Teeth, etc
Dissolve
Mineral
Insoluble Matrix
Soluble Proteins
- Hydrophobic
- Structural framework
- Microenvironment
- Hydrogel character
- Hydrophilic
- Functionality
- Nucleation and Growth
- Asp/Glu, OPO33-, OSO32-
Fish Otoliths (otolin-1)
Enamel (Amelogenins) Nacre (silk fibroin-like protein)
Crystal Growth in Hydrogels
The chemical environment of nucleation is different in a gel
than in a saturated solution:
• Diffusion dominates (convection is suppressed).
• High supersaturations
• Hydrophobic gels can “structure” water and proteins.
Questions
• Why do organisms use hydrogels to control crystal
growth?
• What rules govern the growth mechanisms of crystals in
different types of hydrogels?
• Can we apply crystal growth in gels to non-biological
materials (e.g., organic crystals, oxides) to obtain crystals
with defined morphologies or mechanical properties?
Experimental Design
Agarose
HOH2C
HO
O OH
HOH2C
O OH
O
O
O
O
O
HO
O
O
OH
O
O
OH
n
Freeze-Dried 1 w/v% agarose gel
Crystallization Set-up:
NH3(g) and CO2(g)
(NH4)2CO3
Gel + Ca2+
Experimental Design
Solution Grown Control Crystals
CaCl2 (7 mM)
Agarose gel (1 wt%); CaCl2 (7
mM) on a COOH SAM
Crystallization Set-up:
NH3(g) and CO2(g)
(NH4)2CO3
Gel + Ca2+
Li and Estroff, J. Am. Chem. Soc., 2007, 129, 5480-5483
The internal structure of gel-grown crystals
Solution-Grown Crystals Etched Two Days in DI Water
Gel-Grown Crystals Etched Two Days in DI Water
Li and Estroff, CrystEngComm, 2007, 9, 1153-1155
Continued Etching - Agarose “Crystal Ghosts”
Ca
eV
3 w/v % agarose; Etched in HCl (0.1 M) 10 min.
Questions to Answer:
• Why does the crystal grow around the impurity rather than exclude it?
• Are the crystals single crystals or “mesocrystals”?
• How does the incorporated material alter the mechanical properties of
the crystals?
Where are the organic fibers in the crystals?
LAADF-STEM image of a
thin-section (FIB) of a gelgrown calcite crystal (1 wt%)
SAED (800 nm diameter)
Q u i c kT i m e ™ a n d a
T I F F (U n c o m p re sse d ) d e c o m
a re n e e d e d t o se e t h i s p i c
Q u ic k T im e ™ a n d a
F (U n c om p re s s e d ) d e c o m pr e s s o r
r e n e e d e d t o s e e t h is p ic t u r e .
A = 13 nm; B = 18 nm; C = 14.4 nm
Li, Xin, Muller, and Estroff, Science 2009, 326, 1244-1247
Where are the organic fibers in the crystals?
Electron Tomography
-70° to +70°
1 image/2°
3-D reconstruction
Sobel Filter to highlight
edges.
QuickTime™ and a
YUV420 codec decompressor
are needed to see this picture.
1453 nm x 975 nm x 220 nm
Hanying Li and Huolin Xin
Where are the organic fibers in the crystals?
Lattice image (LAADF-STEM)
Li, Xin, Muller, and Estroff, Science 2009, 326, 1244-1247.
Mechanisms of Incorporation
1) Growth Kinetics
a)
If a particle does not wet the crystal
surface well, it will be pushed away
by a “disjoining force.”
b)
The particle screens the growth
front beneath it from mass transport.
c)
When the growth rate is high
enough, the particle will be pressed
into the crystal.
Chernov, 1984, in Modern Crystallography
2) Crystallization Pressure
RT
−
=
∆
=
σ
pc p1
P
Vm
pc = pressure on the
loaded face of growing
crystal
pl = ambient pressure
Vm = molar volume of
solid phase
Khaimov-Mal'kov, Soviet Physics: Crystallography 1958
Crystallization Pressure and Gel Strength
Fractured and etched
Agarose Type IB
Strength:
98 ± 3 kPa @ 1 w/v%
Agarose Type IX
(hydroxyethylation)
Strength:
9.8 ± 0.4 kPa @ 2 w/v%
Li and Estroff, Adv. Mater., 2009, 21, 470
1 w/v % agarose; 5 mM CaCl2
Crystallization Pressure and Gel Strength
Agarose IX
Agarose IB
Growth Rate and [Ca2+]
1 w/v% agarose Type 1B
Growth Rate and [Ca2+]
5 - 30 mM: Increasing incorporation
30 - 150 mM: Incorporation plateaus
Li and Estroff, Adv. Mater., 2009, 21, 470
Proposed Mechanism: Growth of Polymer-Reinforced Single
Crystals (PRSCs) of Calcite in Agarose Hydrogels
Crystal begins to grow in
porous network.
Can we remove the organic network and preserve the
porous internal structure?
LAADF-STEM of thin section (FIB)
400°C; 1 hour; flowing air
Li, Xin, Muller, and Estroff, Science 2009, 326, 1244-1247.
Internal Structure of Heat-Treated Crystals
QuickTime™ and a
YUV420 codec decompressor
are needed to see this picture.
1405nm x 1196nm x 554nm
Li, Xin, Muller, and Estroff, Science 2009, 326, 1244-1247.
Can we preserve the porous internal structure at lower
temperatures?
Can we preserve the porous internal structure at lower
temperatures?
Specific surface areas
1.23 m2g-1 (1% gel)
5.8 m2g-1 (3% gel)
BET analysis of
crystals treated at 300°C
Li and Estroff, in preparation
SAXS Profiles of Powdered Samples (capillaries)
10000
1% IB agarose
0.75% IB agarose
0.75% IX agarose
Solution grown
Intensity [a.u.]
1000
100
Q-3
10
Q-4
1
0.1
0.01
0.1
1
Nanostar laboratory equipment (Bruker AXS)
Porod’s Law
Q[nm-1]
Barbara Aichmeyer and Anna Schenk (MPI Colloids and Interfaces)
SAXS Profiles of Powdered Samples (tape)
10000
= 1% IB agarose
= 0.75% IB agarose
= 0.75% IX agarose
Intensity [a.u.]
1000
100
Q-3
10
Q-4
1
0.1
0.1
1
-1
Q[nm ]
Biogenic Polymer Reinforced Single Crystals (PRSCs)
Atrina Rigida
Pen shell Mollusk
Prismatic (calcitic) layer
Etching 10 Days in DI Water
Ellen Keene and Hanying Li
What is the internal structure of the prisms?
Li, Xin, Muller, Estroff, in prep.
What is the internal structure of the prisms?
What is the internal structure of the prisms?
Disk-like patches of organic inclusions roughly perpendicular to c axis
What is the internal structure of the prisms?
QuickTime™ and a
YUV420 codec decompressor
are needed to see this picture.
C-axis
QuickTime™ and a
YUV420 codec decompressor
are needed to see this picture.
C-axis
Coherence Length Measurements on Biogenic Prisms
QuickTime™ and a
decom pressor
are nee ded to see th is picture.
QuickTime™ and a
decompressor
are needed to see this picture.
In agreement with incorporation of proteins in ab plane
Berman et al., Science, 1993, 259, 776
Lattice Distortions Due to Organic Inclusions?
QuickTime™ and a
decompressor
are needed to see this picture.
Inclusion via chemical “molecular recognition” or physical “cavities” mechanism?
Pokroy et al. Adv. Mater., 2006, 18, 2363
Preliminary Results on Synthetic Gel-Grown Crystals
Before (filled symbols) and after
burning (open symbols):
1 wt% agarose (diamonds)
2 wt% (triangles)
3 wt% (circles)
Aaron Vodnik, Miki Kunitake, Shef Baker,
Ken Finkelstein and Arthur Woll (CHESS)
Organic inclusions and mechanical properties
Fractured Synthetic Calcite
0 % agarose
Fractured Sea Urchin Spine
2 % agarose
Fracture surface of gel-grown crystal suggests increase in fracture toughness.
Miki Kunitake, Shef Baker
Addadi and Weiner, J. Mater Chem, 1998
Nanoindentation and Orientation
Prisms
Geological
Geologic crystal with a
polished {001} facet
Miki Kunitake, Lauren Mangano, Shef Baker
Nanoindentation and Orientation
Geological
Prisms
0°
60°
0°
60°
Cracking
No cracking
0° Geological {001}
60° Geological {001}
Mechanical Properties of Gel-Grown Crystals
Modulus
90
With incorporated
polymer:
↑ Hardness
↓ Modulus
Indentation Modulus (GPa)
80
70
60
50
40
30
20
10
0
Literature
{104}*
Geologic {104} Solution {104}
*Broz, Cook, Whitney
1% {104}
Geologic {001} Atrina {001}
Hardness
4.5
4
Hardness (GPa)
3.5
3
2.5
2
1.5
1
0.5
Miki Kunitake, John Peloquin,
Shef Baker
0
Literature
{104}*
Geologic
{104}
Solution {104}
1% {104}
Geologic
{001}
Atrina {001}
Possible Deformation Mechanisms
Blocking of crack propagation:
Aizenberg and Hendler, J. Mater Chem, 2004
Inhibition of twinning or slip:
Conclusions and Remaining Questions
•
•
•
•
•
•
•
•
What rules govern the growth mechanisms of crystals in hydrogels?
• Why do the crystals grow around the impurity rather than
exclude it?
How is organic material incorporated into biogenic crystals?
How does the incorporated material alter the physical properties
(e.g., mechanical) of the crystals?
“Physical” vs. “chemical” mechanism for incorporation?
Origins of angular dependence on mechanical properties?
Mechanism of deformation in the presence of organic inclusions?
Why do organisms use hydrogels to control crystal growth?
Can we apply crystal growth in gels to non-biological materials
(e.g., organic crystals, oxides) to obtain crystals with defined
morphologies or mechanical properties?
Acknowledgments
Estroff Research Group
Jason Dorvee
Lauren Mangano
Ellen Keene
John Peloquin
Miki Kunitake
Amy Richter
Hanying Li
Zhi Weh She
Debra Lin
Ruiqi Song
Wangsheng Zhong
Funding & Facilities
NSF CAREER Award
CCMR Seed Grants (NSF-DMR MRSEC)
NIH/NIDCR (R21)
J.D. Watson Young Investigator Award (NYSTAR)
NBTC Seed Grants (NSF-STC)
CCMR facilities
Engineering Learning Initiatives
Collaborators
Barbara Aichmeyer (MPI)
Shefford Baker (MSE)
Ken Finkelstein (CHESS)
David Muller (AEP)
Anna Schenk (MPI)
Aaron Vodnik (MSE)
Huolin Xin (Physics)
Arthur Woll (CHESS)
At high Q (0.8 nm-1 – 2 nm-1) the data were fitted to the following function: I(Q)=a*Q-b
The results are shown in this table:
Sample No.
Sample Name
Position No.
a
∆a
b
∆b
1
1%, IB
1
7.34
0.05
3.46
0.04
1
%, IB
2
7.31
0.05
3.50
0.04
1
%, IB
3
8.84
0.16
3.59
0.11
2
0.75%, IB
1
7.07
0.05
3.38
0.04
2
0.75%, IB
2
7.37
0.07
3.48
0.05
2
0.75%, IB
3
9.17
0.09
3.58
0.06
3
0.75%, IX
1
6.26
0.05
2.77
0.04
3
0.75%, IX
2
5.71
0.04
2.93
0.04
3
0.75%, IX
3
6.33
0.05
2.86
0.05
The parameter b (slope in the double-logarithmic plot) is related to the interface (roughness or fractal dimension,
electron density profile of the interface). The parameter a is proportional to the scattered intensity and it is expected
to increase with the amount of the hydrogel inclusions.
For samples 1 and 2, the contribution of the larger structures cannot be neglected and the slope b at high Q is
affected by a contribution from these larger structures. Optimizing the sample preparation could help (powder samples
with random orientation but all particles with a size of some tens of µm). For sample 3, the behavior at high Q should
represent the small inclusions since the “low Q part” is much smaller.
SAXS profiles of powdered samples measured in scotch tape
3 positions were measured for each sample. The 3 scattering profiles for each of the samples (normalized by ln(τ))
are now shown in the same plot (for a comparison between the different samples please see the previous page).
10000
10000
sample 2
sample 1
1000
Intensity [a.u.]
Intensity [a.u.]
1000
100
10
1
100
10
1
0.1
0.1
0.1
-1
1
Q [nm ]
0.1
Q [nm-1]
1
10000
sample 3
There is some variation between the different
positions (within one sample), but at high Q the
data sets look very consistent. The scattering at
high Q presumably is dominated by the nanosized hydrogel inclusions whereas the low Q
region is affected by any kind of larger
structures, such as the particle size / surface or
larger pores / inclusions.
Intensity [a.u.]
1000
100
10
1
0.1
0.1
Q [nm-1]
1
Tests for sample 3, position 2
10000
P/Q4+C/Q*exp(-Q2R2/4) (fit)
P/Q4
C/Q*exp(-Q2R2/4)
a*Q-b (fit)
Intensity (a.u.)
1000
100
P=0.26
C=17.3
R=2.4 nm (radius of cylinders)
a=5.71
b=2.93
10
1
0.1
0.1
1
Q (nm-1)
For sample 3 we tried some further evaluations in addition to fitting a power law at high Q (blue line). At low Q we
fitted a Porod law for larger structures (slope -4) plus the Guinier approximation for cylinders (full red line, the used
equations appear in the legend of the graph). This yielded a cylinder radius of 2.4 nm. Does it make sense? I am not
sure the cylinder model is a very good one. Other functions, e.g. for polymer chains might be better.
For any further interpretation of the results it will be good to know more about the differences between the samples
(chemical composition, size, structure and amount of inclusions). Furthermore, the sample preparation (powdering,
filling into containers) needs to be optimized in order to make a good quantitative analysis. Calibration/comparison
with other methods could also help.
In addition to what is shown here we also tried measurements at lower angles at the synchrotron, but this experiment
did not yield any additional information.
All crystals at 0 degree
Orientation, 2500uN
Inden
tation
Modu
lus
Literature
{104}
Geologic
{104}
Solution
{104}
1% {104}
Geologic
{001}
Atrina
{001)
78.1
82.73
77.84
67.18
72.07
70.43
All values in GPa.
Std.
Dev
5.2
1.081
1.74
2.86
3.56
5.02
Hardn
ess
2.21
2.6
2.49
3.4
2.28
3.68
Std.
Dev
0.16
0.062
Literature (Broz, Cook, Whitney) using depth sensing
instrumentation, aka nanoindentation
17 indents 1 crystal, but many other crystals tested and data
similar.
0.05
Grown by standard gas diffusion 5mM CaCl2. 3 crystals 20
indents.
0.14
Grown by standard gas diffusion 5mM CaCl2. Measurements
done by sprinkling crystals onto indenter chuck, polishing
down. 3 crystals 26 indents
0.12
18 indents 1 crystal, but many other crystals tested and data
similar
0.22
40 indents on 5 crystals, within -10 to 10 degree azimuthal
angles. (001) orientation a little off.
Mechanical Properties of Biogenic PRSCs
Aizenberg and Hendler
J. Mater Chem, 2004
Fractured Synthetic Calcite
Addadi and Weiner, J. Mater Chem, 1998
Fractured Sea Urchin Spine
How much agarose is inside of the crystals?
Li and Estroff, Adv. Mater., 2009, 21, 470
Geological Minerals
1
2
R. Weller/Cochise College
1) Calcite, CaCO3
2) Aragonite, CaCO3
3) Apatite, Ca10(PO4)6(OH)2
Symmetric
Regular
Brittle
3
Biominerals
Irregular
Strong
Pearls
Bone
Brittle Star
Biominerals: Composite Materials
Organic matrix:
- Collagen (bone, teeth)
- Chitin (mollusk shells)
- Silk fibroin (mollusk shells)
- Other macromolecules
Inorganic mineral:
- Ca5(PO4)3(OH,F) (bone, teeth)
- CaCO3 (shells, sea urchins)
- SiO2 (plants, sea plankton)
- Iron oxides, other carbonates
Evolutionarily optimized for:
- Fracture Toughness
- Optical Properties
- Morphology
Fractured Sea Urchin Spine
Addadi and Weiner, J. Mater Chem, 1998
Aizenberg and Hendler, J. Mater Chem, 2004
Biominerals: Composite Materials
Organic matrix:
- Collagen (bone, teeth)
- Chitin (mollusk shells)
- Silk fibroin (mollusk shells)
- Other macromolecules
Inorganic mineral:
- Ca5(PO4)3(OH,F) (bone, teeth)
- CaCO3 (shells, sea urchins)
- SiO2 (plants, sea plankton)
- Iron oxides, other carbonates
Evolutionarily optimized for:
- Fracture Toughness
- Optical Properties
- Morphology
Can we learn synthetic strategies from
biology to apply to other materials?
Calcitic lenses on brittle stars
Addadi and Weiner, J. Mater Chem, 1998
Aizenberg and Hendler, J. Mater Chem, 2004
Weiner and Wagner, Annu. Rev. Mater. Sci. 1998
Control During Growth: Morphology
Mature Sea Urchin Spicule
• Diffracts X-Rays as a single crystal
• 0.02 wt% protein in mineral
• Fractures conchoidally
Aizenberg et al., JACS, 1997
Albeck et al., JACS, 1993
Amino Acid Composition (>3%):
AsX
15.5% Ala
8.0%
GlX
12.7% Val
3.9%
Ser
4.4%
Leu
3.5%
Thr
6.5%
Pro
10.1%
Gly
19.4% Arg
5.9%
Growth Rate and [Ca2+]
1 w/v% agarose
5 - 30 mM: Increasing incorporation
30 - 150 mM: Incorporation plateaus
Theoretical mass fraction of
agarose in crystal:
Wa = C/[C+ρc(1-C/ρa)]
where, C = [agarose] in g/mL
ρc = 2.71 g/cm3
ρa = 1.64 g/cm3
Bound waters must also be
incorporated with the agarose fibers.
Li and Estroff, Adv. Mater., 2008, in press
0.37%
0.18%
0.09%