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2nd World Scientific Congress Challenges in Botanical Research
and Climate Chan e
The natural atterns of self-cleanin surfaces:
Delft, The Netherlands, 29 June - 4 July 2008
Micro-nanotopography analysisof superhydrophobic leaves
Eduardo A. Favret and Ana M. Molina
Jardn Botnico A. Ragonese
INTA - Argentina
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Bionics Biomimetism
The study of theformation, structure, or
produced substancesand materials and
biological mechanisms
Interdisciplinary Science
an processes espec a y
for the purpose ofsynthesizing similarroducts b artificial
Biological surfacesmechanisms which
mimic natural ones."
Functional properties Lotus(Self-Cleaning surface)
Moth Eye(Antirreflective surface)
Gecko(Antifriction surface) (Dry-adhesive surface)
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Lotus EffectSelf-Cleaning Surfaces
Superhydrophobicity
ys ca opograp y Chemical (composition)
Multiscale roughness
(long chains C, H and O)
low surface energy materials/coatings or by introducing roughness.
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Multiscale roughness
Applications of self-cleaning surfacesWindshields exterior aints for buildin s navi ation-shi s and
utensils, roof tiles, textiles and reduction of drag in fluid flow
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Superhydrophobic (SH) condition
con ac ang e < 10 (sliding angle) a r < 10 (Hysteresis)
The Fakir Effect
Drop bouncing on a SH surface
Courtesy ofDr. D. Qur (France)
Courtesy of Dr. D. Qur (France)
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Research lines in SH surfaces
Chemical compositionlow free ener surface
Fabrication ofmicro/nano-
Binary structure: Micro-nano topographyHierarchical structures (70-500nm, 3-100m)
.
D. Qur B. BhushanM. Nosonovsky
C. Neinhuis
K. KochN. Patankar
S. Herminghaus T. McCarthy
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Journals and Paperson SH surfaces
BARTHLOTT, W. and C. NEINHUIS. 1997. Purity of the sacred lotus, or escape fromcontamination in io ogica sur aces. P l a n t a . 202: 1-8.
OTTEN, A. and S. HERMINGHAUS. 2004. How Plants Keep Dry: A Physicists Point of View.
La n g m u i r . 20: 2405-2408.
QUR, D. and M. REYSSAT. 2008. Non-adhesive lotus and other hydrophobic materials.Ph i l . T r a n s . R . Soc . A . 366: 15391556.
NOSONOVSKY, M. and B. BHUSHAN. 2008. Roughness-induced superhydrophobicity: a
way to design non-adhesive surfaces. Jo r n a l o f P h y s ic s : Co n d e n s . M a t t e r . 20 (2008)225009 (30pp).
PATANKAR, N. A. 2004. Mimicking the Lotus Effect: Influence of Double Roughness- . . .
GUO, Z. and W. LIU. 2007. Biomimic from the superhydrophobic plant leaves in nature:Binary structure and unitary structure. P la n t S ci e n c e . 172: 1103-1112.
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Our Research Objective
Describe and find the topographical patternso e super y rop o c sur aces
Is there any difference between the binary and unitary structures?
Approach
Topograp ica c aracterization o ea samp esSEM-ESEM Images
Quantitative Measurementsana ys sana ys s
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Leaf Samples
Brassica Xanthosoma and Colocasia
TropaeolumOryza
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Wetting conditions
Tropaeolum
Colocasia
Brassica
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Micro-nanostructure of leaf surfaces
- -Microstructure: micro-bumps (diameter 2-20m, distance 20-40m,height 10-30m)
,
Colocasia
Nelumbo
Courtesy of Dr. C. Neinhuis (Germany)
Xanthosoma Brassica
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The peaks of the RIMAPS spectrumindicate main angular directions of the
topographic pattern
This technique consists basically of rotating the image using availableal orithms of commercial software and calculatin the x-ste of the two-dimensional Fourier transform for each y-line of the new image obtained
after rotation. As a consequence, averaged power spectra are obtained foreach angular position. The corresponding maximum values are plotted asa function of rotation an le obtainin the RIMAPS s ectrum.
1.0
0.6
0.8
APS(u.a.)
0 50 100 150 200 250 300 3500.2
0.4
gra os
FUENTES, N. and FAVRET, E. (2002): A new surface characterization technique: RIMAPS
(Rotated Image with Maximun Average Power Spectrum), Jo u r n a l o f M i cr o s c o p y . 206, 72-83.
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RIMAPS Results
Co l o c a s i a
(adaxial side)X an t h o so m a
(abaxial side)
Co l o c a s i a
Epicuticular wax
0.8
1.0Xan2 400xCol7.10 400x
.)
0.8
1.0Col7.10 400xT21a col 6400x
.)
0.2
0.4
0.6
MAPS(a
.
0.2
0.4
0.6
MAPS(a
.
0 30 60 90 120 150 180
0.0
RI (degrees)
0 30 60 90 120 150 180
0.0
RI (degrees)
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RIMAPS Results (cont.)
X a n t h o s o m a (abaxial side)
Xanthosoma500x
Ideal micro-pattern
0.8
1.0
.)
0.2
0.4
0.6
MAPS(a
.
0 20 40 60 80 100 120 140 160 180
0.0
.
RI (degrees)
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RIMAPS Results (cont.)
O r y z a (adaxial side)
1.0
Oryza500x
0.6
0.8
.u.)
Oryza2000x
0.2
0.4
MAPS
(
0 20 40 60 80 100 120 140 160 1800.0
RI (degrees)
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RIMAPS Results (cont.)
T r o p a e o l u m (adaxial side)
0.8
1.0
u.)
ropaeo um x
Tropaeolum800x
Tropaeolum1600
0.2
0.4
.
MAPS(a.
0 20 40 60 80 100 120 140 160 180
0.0
RI (degrees)
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B r a s s i c a (adaxial side)
0.8
1.0
u.)
Brassica1500x
0.2
0.4
.
MAPS(a.
0 20 40 60 80 100 120 140 160 1800.0
RI (degrees)
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RIMAPS Polar Graphs
Xanthosoma
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RIMAPS Polar Graphs
B r a s s i c a
T r o p a e o l u m
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Conclusions
RIMAPS results:The topographical pattern shows difference depending on the size ofthe studied area for the same s ecies.The Colocasia micro-pattern has a great similarity with its nano-patternThere are different micro-patternsColocasia andXanthosoma (abaxial side) has similar patterns for low
Brassica has a nano-pattern almost similar to the micro-structure ofXanthosoma (abaxial side)
u ure ana yses:Nano-pattern (epicuticular wax)Leaf with unitary structure (e.g. Ramee -Boehmeria iongispica steud-)Alchemilla vul aris h dro hilic hairs on a h dro hobic substrateHydrophilic leaf surfaces (e.g. Magnolia grandiflora)
Herbarium samples
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BotanicalBotanical GardenGarden AA.. RagoneseRagonese
A future centre in research and education on Biomimetism
a ure o ers us e c en an e ec ve mo e s or edevelopment of mechanicals tools, computational algorithms andnew materials
We can learn from Nature new production processes, withouttoxic waste and pollution
disappearing
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Thank you!
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