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Thunder Lecture III. Shanghai Institute for Advanced Studies. Fudan University 04.04.2006. Nano-Bionik. Micro- and Nanotechnology in Nature. Ingo Rechenberg. Bionics Biomimicry Biomimetics. What is Bionik ?. The study of the results of biological evolution.

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Thunder Lecture III

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Shanghai Institute for Advanced Studies

Fudan University 04.04.2006

Nano-Bionik

Micro- and Nanotechnology in Nature

Ingo Rechenberg


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Bionics Biomimicry Biomimetics

What is Bionik ?

The study of the results of biological evolution

from the engineering point of view

from the engineering point of view

Learning from nature‘s way of engineering


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Bacteria flagellum

Micro&nano-structured biological surfaces

Biological selfassembly

Protein machines

Biological receptors

Muscle filaments

Nano-Bionik


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The topics

The Lotus-Flower-Effect: Self-cleaning property through hydrophobic micro-dots.

The Moth-Eye-Effect: The art to be invisible through optical nano-burls.

The Gecko-Foot-Effect:Sticking on the wall through elastic nano-hairs.

The Sand-Skink-Effect:Reduction of friction and wear through nano-thresholds.

The Darkling-Beetle-Effect:Collecting dew through hydrophilic/hydrophobic micro-spots.

The Shark-Scale-Effect:Turbulence reduction through longitudinal micro-grooves.

The Water Strider-Effect: To keep dry through micro-hairs with nano-ridges.


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Nano-spikes

Nano-thresholds

Nano-grooves

Nano-humps

Nano-burls

Nano-bumps

Nano-ladders

Nano-ribs

Nano-knobs

Nano-patterns in nature

?

?


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The sacred Lotus flower is a symbol of purity in Asian religions.

The Lotus-Flower-Effect


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Honey rolls down from a “Lotus-Effect-spoon” religions.

The Lotus-Effect®

Water droplets roll down the leaf of the Lotus flower

Glue rolls down the leaf of the Lotus flower

A droplet takes up the dirt while rolling down


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30 religions.μm

Microrelief of the leave

The development of the Lotus-Effect® paint

Bionik-product

Self cleaning


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Lotusan facade paint religions.

Standard facade paint

Test areas at the wall of my house after 4 years


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Adhesion > Cohesion religions.

Adhesion < Cohesion

Surface tension and wetting angle

Adhesion << Cohesion


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smooth surface religions.

Lotus-Effect® surface

The Lotus-Effect in action


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Lotus-Effect religions.® roof tile

Lotus-Effect® tie

Prof. Wilhelm Barthlott


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1 religions.×1 cm

engineering imitation

Secondary structure

Lotus leaf

The Lotus-Effect extended


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Water droplet religions.

Water droplet

The Lotus-Effect extended



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130 x religions.

420 x

1050 x

4120 x

Micro-burls

100nmØ

Micro-optics of the moth eye


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< religions.

l

light

Air

Optical transparent layer

Reflection of the light is avoided by a continuously increasing refractive index of the optical medium

Glass

Deception of the light

The little burls on the surface of the optical medium work as a gentle increase of the refractive index


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All the light is captured by th eye religions.

Moonlight is not mirrored (predatory!)

Night-flying insect



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Technological imitation of the nanostructure of a moth eye. Periodicity of the burls: 300 nm.

Glass pane with

Moth-Eye-Effect


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The Moth-Eye-Effect Periodicity of the burls: 300 nm.


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The wonder of the Gecko toes Periodicity of the burls: 300 nm.


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500 Periodicity of the burls: 300 nm.000000 nanohairs

2 kg (theoretically)

Photo: M. Moffet

Geckos get a grip using Van-der-Waals-forces

Gecko sticking at the wall


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The seta has 1 Periodicity of the burls: 300 nm.000 nanohairs

The Gecko toe has 500000 microhairs (setae)

Nanostructure of the Gecko toe


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Adhesion effect through Periodicity of the burls: 300 nm.

Van-der-Waals-forces

The Gecko effect

Technical surface 1

Contact area

Technical surface

Technical surface 2

Nanohairs !

Large contact area

large adhesion force

Small contact area

small adhesion force

Microhair


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Synthetic Gecko hairs Periodicity of the burls: 300 nm.

necessary for spider man

(New Scientist 15. 05. 2003)


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Gecko-Tape Periodicity of the burls: 300 nm.


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? Periodicity of the burls: 300 nm.

The Sandfish lives in the Sahara desert

The Sandfish-Effect


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Sandfish ? Periodicity of the burls: 300 nm.

Fishing rod


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0 s Periodicity of the burls: 300 nm.

The Sandfish

¼ s

½ s

dives down


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Characteristics of the sandfish scales Periodicity of the burls: 300 nm.

M. Zwanzig, IZM

Friction

Abrasion

sand flow

Electron emission

8µm


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My Sahara Lab Periodicity of the burls: 300 nm.

Field

work

in the

Sahara

GPS:

N 31°-15‘–02“

W 03°-59‘–13“

Erg Chebbi


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Simple apparatus to measure the dynamic friction coefficient of flowing sand

Sand tubule

Angular scale

Object platform

Hand lever



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20 of flowing sand°

Sand flow is moving

18°

Sand flow stops

Sandskink

Measurement of the angle of sliding friction


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0 of flowing sand

40

0

35

0

30

sliding angle

0

25

n

0

20

o

n

d

l

f

o

n

ss

e

l

0

a

y

T

15

a

S

N

l

teel

k

G

n

0

10

i

S

k

S

Sahara-Measurement 2002

0

5

0

0

Sliding friction: Sandfish versus engineering materials



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58 of flowing sand %

Sand-cylinder measurements 2003

Steel = 19°

Sliding angle:

Sandskink = 12° Caudal

Sandskink = 18° Cranial


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50 of flowing sandnmØ

Sandfish scale under the electron mikroscop (REM)

scale

Sand sflow

8µm

at the back

at th belly


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Sand flow of flowing sand

6µm

Oblique view of the nano-thresholds


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Sliding direction of flowing sand

Size comparison

Grain of sand upon the thresholds



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The sandskink always looks shiny of flowing sand

while

Man-made things soon get blunt in the desert wind !

The resistance to abrasion


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Simple apparatus for the abrasion tests of flowing sand

Sandfunnel

Sandblast

Objectplatform


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Impact point of the sandblast of flowing sand

Impact time: 10 hours !

Steel

Abrasive spot:

Glass


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Glass Magnification ≈ of flowing sand200

Sand abrasion under the microscope

2 hours impact time

20 cm blast height

Scotch tape protected

Sand blast

Sandfish Magnification ≈1000

Sandfish Magnification ≈1000

Afterward

Before


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Kenyan Sandboa of flowing sand

Sandskink

Parallel Evolution


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Sands of flowing sandkink

Kenyan Sandboa

Sandskink

Parallel Evolution


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Aporosaura anchita of flowing sand

Sand-diving lizard in the Namib desert

Namib


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The Mongolian Death Worm of flowing sand

Allghoi khorkhoi

lives in the Ghobi dersert

?

Ghobi



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Night photo of flowing sand

Exposure time 20 s

Discharge spark on the back of the sandskink after a sand storm




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Electron acceptor of flowing sand

Electron donator

Sandskink scale

Tail

Head

Directed tribo-electricity on the sandskink scales


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Observed by Ern of flowing sandő Németh

https://fridolin.tu-freiberg.de/archiv/pdf/VerfahrenstechnikNXmethErnX748129.pdf

Neutrally charged grain of plastic with oppositely charged spots


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Observed in Sahara of flowing sand

Sticking chain of sandgrains

Neutrally charged grain of sand can have oppositely charged spots


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Hypothesis: of flowing sand

The directed triboelectric experiment indicates the ease of an electron exchange from and to the Sandfish skin

Electric levitation hypothesis


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Sandgrain of flowing sand

The effect may work for some seconds, time enough for the sandfish to escape. After that the neutralised charge has to be refilled.

Sandfish

Electric levitation hypothesis


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Modern Sand Boarding of flowing sand



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Fog catching in of flowing sand

the Namib desert

made by nature

and

made by humans


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10 of flowing sandmm

Andrew R. Parker and Chris R. Lawrence

Darklingbeetleofthe Namib desert

(Stenocara sp.)

Hydrophilic peaks

Hydrophobic burled lowland

similar to the Lotus-Effect®


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Hydrophobic burls of flowing sand

Fog droplets

Hydrophilic hills


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Hydrophobic burls of flowing sand

Fog droplets

Hydrophilic hills

Condensation


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Hydrophobic burls of flowing sand

Fog droplets

Hydrophilic hills

To the mouth of the beetle

Collected dew


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Waxen surface of flowing sand

Spray

Air flow

Glass spheres

Fan

Experiment of Parker and Lawrence


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Shark scale of flowing sand

The Shark-Scale-Effect


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0,5 of flowing sandmm

The groove structure of the shark scales


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s of flowing sand

0

o

60

-2

s

-4

s

2

o

45

-6

s

-8

-10

0

6

2

4

D

W

Sawtooth-Grooves

W

0

Sawtooth-Grooves

%

Trapezoidal-grooves

Rectangular- grooves

Trapezoidal-grooves

s

2

Rectangular- grooves

*

s

BECHERTs experiments in the Berlin oil-channel




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The Water-Strider-Effect of flowing sand



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Nano-grooves of flowing sand

Water

strider

Xuefeng Gao & Lei Jiang, Beijing

20μm

200nm


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Robostrider of flowing sand

Development of an artificial water strider

B.Chan, D.Hu



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10 of flowing sandmm

The hair of the water spider, a model for a new waterproof suit


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Thank for your attention of flowing sand

www.bionik.tu-berlin.de


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