The document describes experiments using an environmental scanning electron microscope to generate 3D reconstructions of membrane structures from 2D image slices. Membrane samples were embedded in resin and ultramicrotomed into thin sections for imaging. Image stacks from multiple samples were assembled into 3D models and analyzed to calculate membrane pore characteristics and water flux measurements, validating the 3D reconstruction method. The results provide a quantitative view of membrane nanostructure-property relationships not possible with conventional techniques.

1. MicroPES®2F
Herbert Reingruber
Armin Zankel
May 30th, 2012
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2. 3D Visualization of the membrane structure
• Experimental Setup
• Sample Preparation
• Image Processing
• Results
Conclusion
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3. SEM
High vacuum in the sample chamber
necessary
~ 10-4 Torr
ESEM
E(nvironmental) SEM
additional variable pressure range:
0.1 - 20 Torr
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4. The Environmental Scanning
ESEM Quanta 600 F
Electron Microscope (ESEM)
A Microlab for Science and Industry
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5. The Environmental Scanning
Electron Microscope (ESEM)
ESEM: Environmental SEM
LV-CSEM: Low Vacuum Conventional SEM
CSEM: Conventional SEM
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6. The Environmental Scanning
Electron Microscope (ESEM)
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7. http://www.gatan.com/sem/3dmicrotomy.html
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=524270
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8. Experimental setup
in situ ultramicrotomy
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9. Experimental setup
in situ ultramicrotomy
History: Stephen B. Leighton, 1981
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10. Institute for Electron Microscopy and Fine Structure Research
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11. Experimental setup
in situ ultramicrotomy
Preparation and Positioning of the Specimen
Embedding in resin, staining
Precutting with ultramicrotome
Positioning with light microscope and CCD-Camera
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12. First steps: paper
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13. First steps: paper
coat
Preparation:
Embedding in resin
No staining: intrinsic
material contrast
fibers
Precutting
resin
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14. First steps: paper
1. cut 50. cut 100. cut
100 cuts of a paper specimen (thickness of the slices: 200nm, micrograph: BSE) are assembled
into a three dimensional (3D) model (unit: µm).
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15. First steps: paper
3D model of the fillerparticles of the paper 3D model of the fibers in the paper
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16. air side roll side
DuraPES®200
20 µm 20 µm
MicroPES®2F
20 µm 20 µm
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17. Institute for Electron Microscopy and Fine Structure Research
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18. 0.5 mm
Diamond knife
Sample mounted on the rivet
100 µm
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19. Institute for Electron Microscopy and Fine Structure Research
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20. DuraPES®450 a b
10µm10µm 10µm 10µm 10µm11.4µm
Stack#2 (30.7 x 61.4 x 10.6) µm
Stack #2 Stack #3 c d
approx. 150µm
10µm 10µm 10µm 3.6µm
Stack #1
Stack#1 (39.5 x 163.0 x 45.0) µm Stack#3 (37.5 x 25.6 x 10.0) µm
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21. [µm]
a b
10µm10µm 10µm 10µm 10µm11.4µm
[µm]
[µm]
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22. a b c d
a b c [µm]
d [µm]
[µm] [µm]
30 25 25
30 20 [µm] 12,5 12,5
20 [µm] 10 [µm]
[µm] 10
10 10 10
10
5 5 5 5
0 0 0
0
5 5 4
5
10 10 [µm] 10 [µm] 8
[µm] [µm]
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23. MicroPES®4F DuraPES®450 Sartorius 15406
surface A
surface A
surface A
(air side)
(air side)
(air side)
10µm
10 µm 10 µm 10 µm
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24. specifically measured
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25. MicroPES®4F DuraPES®450 Sartorius 15406
air side air side air side
images reconstructions
SEM 3D
5 µm 5 µm 5 µm
roll side roll side roll side
reconstructions
3D
images
SEM
5 µm 10 µm 5 µm
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26. 3D reconstruction SEM image
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27. Results
sub porous structure
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28. 3D model of the membrane structure
Calculation of the absolute permeability
Calculation of the pure water flux
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29. Calculation of the pure water flux: some equations
pA pB
Q Q
A
l
Darcy´s Law:
Ohm‘s Law:
with
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30. MicroPES®4F DuraPES®450 Sartorius 15406
surface A
surface A
surface A
(air side)
(air side)
(air side)
10µm
10 µm 10 µm 10 µm
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31. specifically measured
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32. • 3D reconstructions reproduce the surface
morphology, the pore structures etc.
• The gained parameter profiles give quantitative
values of the inner pore structure
• The results of the fluid simulations are in
agreement with the experiment
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33. [1] W. Denk, H. Horstmann.
Serial Block‐Face Scanning Electron Microscopy to Reconstruct Three‐Dimensional Tissue Nanostructure.
PLoS Biol, 2 (2004) e329.
[2] M. Ulbricht, O. Schuster, W. Ansorge, M. Ruetering, and P. Steiger.
Influence of the strongly anisotropic cross‐section morphology of a novel polyethersulfone microfiltration membrane on filtration performance.
Separation and Purification Technology, 57 (2007) 63.
[3] R. Ziel, A. Haus, and A. Tulke.
Quantification of the pore size distribution (porosity profiles) in microfiltration membranes by SEM, TEM and computer image analysis.
J.Membr.Sci., 323 (2008) 241.
[4] H. Reingruber, A. Zankel, C. Mayrhofer, and P. Poelt.
Quantitative characterization of microfiltration membranes by 3D reconstruction.
J.Membr.Sci. 372 (2011) 66‐74.
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34. Ing. Claudia Mayrhofer PD Dipl.-Ing. Dr. Peter Pölt
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35. Dipl.-Ing. Herbert Reingruber
Thank you for your attention!
Time for Discussion
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