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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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slide2
Shanghai Institute for Advanced Studies

Fudan University 04.04.2006

Nano-Bionik

Micro- and Nanotechnology in Nature

Ingo Rechenberg

slide3
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

slide4
Bacteria flagellum

Micro&nano-structured biological surfaces

Biological selfassembly

Protein machines

Biological receptors

Muscle filaments

Nano-Bionik

slide5
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.

slide6
Nano-spikes

Nano-thresholds

Nano-grooves

Nano-humps

Nano-burls

Nano-bumps

Nano-ladders

Nano-ribs

Nano-knobs

Nano-patterns in nature

?

?

slide8
Honey rolls down from a “Lotus-Effect-spoon”

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

slide9
30μm

Microrelief of the leave

The development of the Lotus-Effect® paint

Bionik-product

Self cleaning

slide10
Lotusan facade paint

Standard facade paint

Test areas at the wall of my house after 4 years

slide11
Adhesion > Cohesion

Adhesion < Cohesion

Surface tension and wetting angle

Adhesion << Cohesion

slide12
smooth surface

Lotus-Effect® surface

The Lotus-Effect in action

slide13
Lotus-Effect® roof tile

Lotus-Effect® tie

Prof. Wilhelm Barthlott

slide14
1×1 cm

engineering imitation

Secondary structure

Lotus leaf

The Lotus-Effect extended

slide15
Water droplet

Water droplet

The Lotus-Effect extended

slide17
130 x

420 x

1050 x

4120 x

Micro-burls

100nmØ

Micro-optics of the moth eye

slide18
<

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

slide19
All the light is captured by th eye

Moonlight is not mirrored (predatory!)

Night-flying insect

slide21
Technological imitation of the nanostructure of a moth eye. Periodicity of the burls: 300 nm.

Glass pane with

Moth-Eye-Effect

slide24
500000000 nanohairs

2 kg (theoretically)

Photo: M. Moffet

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

Gecko sticking at the wall

slide25
The seta has 1000 nanohairs

The Gecko toe has 500000 microhairs (setae)

Nanostructure of the Gecko toe

slide26
Adhesion effect through

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

slide27
Synthetic Gecko hairs

necessary for spider man

(New Scientist 15. 05. 2003)

slide29
?

The Sandfish lives in the Sahara desert

The Sandfish-Effect

slide30
Sandfish ?

Fishing rod

slide31
0 s

The Sandfish

¼ s

½ s

dives down

slide32
Characteristics of the sandfish scales

M. Zwanzig, IZM

Friction

Abrasion

sand flow

Electron emission

8µm

slide33
My Sahara Lab

Field

work

in the

Sahara

GPS:

N 31°-15‘–02“

W 03°-59‘–13“

Erg Chebbi

slide34
Simple apparatus to measure the dynamic friction coefficient of flowing sand

Sand tubule

Angular scale

Object platform

Hand lever

slide36
20°

Sand flow is moving

18°

Sand flow stops

Sandskink

Measurement of the angle of sliding friction

slide37
0

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

slide39
58 %

Sand-cylinder measurements 2003

Steel = 19°

Sliding angle:

Sandskink = 12° Caudal

Sandskink = 18° Cranial

slide40
50nmØ

Sandfish scale under the electron mikroscop (REM)

scale

Sand sflow

8µm

at the back

at th belly

slide41
Sand flow

6µm

Oblique view of the nano-thresholds

slide42
Sliding direction

Size comparison

Grain of sand upon the thresholds

slide44
The sandskink always looks shiny

while

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

The resistance to abrasion

slide45
Simple apparatus for the abrasion tests

Sandfunnel

Sandblast

Objectplatform

slide46
Impact point of the sandblast

Impact time: 10 hours !

Steel

Abrasive spot:

Glass

slide47
Glass Magnification ≈200

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

slide48
Kenyan Sandboa

Sandskink

Parallel Evolution

slide49
Sandskink

Kenyan Sandboa

Sandskink

Parallel Evolution

slide50
Aporosaura anchita

Sand-diving lizard in the Namib desert

Namib

slide51
The Mongolian Death Worm

Allghoi khorkhoi

lives in the Ghobi dersert

?

Ghobi

slide53
Night photo

Exposure time 20 s

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

slide56
Electron acceptor

Electron donator

Sandskink scale

Tail

Head

Directed tribo-electricity on the sandskink scales

slide57
Observed by Ernő Németh

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

Neutrally charged grain of plastic with oppositely charged spots

slide58
Observed in Sahara

Sticking chain of sandgrains

Neutrally charged grain of sand can have oppositely charged spots

slide59
Hypothesis:

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

Electric levitation hypothesis

slide60
Sandgrain

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

slide63
Fog catching in

the Namib desert

made by nature

and

made by humans

slide64
10mm

Andrew R. Parker and Chris R. Lawrence

Darklingbeetleofthe Namib desert

(Stenocara sp.)

Hydrophilic peaks

Hydrophobic burled lowland

similar to the Lotus-Effect®

slide65
Hydrophobic burls

Fog droplets

Hydrophilic hills

slide66
Hydrophobic burls

Fog droplets

Hydrophilic hills

Condensation

slide67
Hydrophobic burls

Fog droplets

Hydrophilic hills

To the mouth of the beetle

Collected dew

slide68
Waxen surface

Spray

Air flow

Glass spheres

Fan

Experiment of Parker and Lawrence

slide69
Shark scale

The Shark-Scale-Effect

slide70
0,5mm

The groove structure of the shark scales

slide71
s

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

slide76
Nano-grooves

Water

strider

Xuefeng Gao & Lei Jiang, Beijing

20μm

200nm

slide77
Robostrider

Development of an artificial water strider

B.Chan, D.Hu

slide79
10mm

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

slide80
Thank for your attention

www.bionik.tu-berlin.de