a gecko-inspired chip-integrated reversible...
TRANSCRIPT
Kimberly Turner Associate ProfessorMechanical Engineering
Michael Northen, PostdocInstitute for Collaborative Biotechnologies
University of California, Santa Barbara
Kimberly Turner Associate ProfessorMechanical Engineering
Michael Northen, PostdocInstitute for Collaborative Biotechnologies
University of California, Santa Barbara
A Gecko-Inspired Chip-Integrated Reversible Adhesive
A Gecko-Inspired Chip-Integrated Reversible Adhesive
27 October 2006Slide 2 Turner and Northen
OutlineOutline• Introduction & Motivation• Gecko Adhesion Mechanism• Integrated Micro/Nanostructures
-adhesion testing• Adhesion Control
-adhesion testing
• Introduction & Motivation• Gecko Adhesion Mechanism• Integrated Micro/Nanostructures
-adhesion testing• Adhesion Control
-adhesion testing
Slide 3
Gecko Paper Frequency
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# Pa
pers
Slide 4
setaeE. Arzt & S. Gorb
Biology Nanoscience
MEMS & Nanotechnology
Biomimetics
Slide 5
Stanford Report, March 12, 2003
Mimicking cockroaches' 'mechanical intelligence'Development of legged robots could help in navigating disaster sites, other dangerous and difficult-to-reach places
BY BRONWYN BARNETT
Mark Cutkosky
Slide 6
“Fine hair” adhesive motif• Also found in other lizards and insects
– e.g. anoles, crickets, beetles, flies, spiders.
Slide 7
Adhesion MechanismAdhesion Mechanism
Slide 8
van der Waals
Short range London Dispersion Force
F = n H R / 6D2
H = Hamaker Constant (surface property)R = RadiusD = Cut-Off Distance (variable)n = Number of Contacts
Slide 9
S. Gorb
Arzt, Gorb, Spolenak PNAS 2003
Slide 10
Autumn, K., et al., PNAS, 99(19): p. 12252-12256 (2002). This hierarchical construction makes the lizard adhesive system elastically very soft on all relevant length scales (from mm to nm).
Persson and Gorb, J. Chem. Phys. (2003).
Multi-scale conformal structure
Slide 11
Controllable Conformance
Slide 12
“The use of a soft rather than solid base has dramatically (by nearly 1,000 times) improved gecko tape to support the weight of a suitably light familiar object(a toy in Fig. 4).”
Geim, A. K., Dubonos, S. V., Grigorieva, I. V., Novoselov, K. S. & Zhukov, A. A. Nature Materials 2, 461-463 (2003).
Slide 13
Controllable Conformance
Slide 15
Fabrication
27 October 2006Slide 16 Turner and Northen
27 October 2006Slide 17 Turner and Northen
27 October 2006Slide 18 Turner and Northen
27 October 2006Slide 19 Turner and Northen
27 October 2006Slide 20 Turner and Northen
Slide 21
Nanorod Properties
• Diameter ~ 200 nm• Length ~ 4 µm • Beta Keratin• Modulus ~ 1-15 GPa• High Density• No Condensation• Ultra-Hydrophobic,
Contact Angle ~170°
Courtesy Edward Arzt (S. Gorb)
27 October 2006Slide 22 Turner and Northen
Growing NanorodsGrowing Nanorods
E. Schäffer, Thrun-Albrecht, T., Russell, T.P., Steiner, U., Nature 403, 874 (2000).
27 October 2006Slide 23 Turner and Northen
Nanowire SynthesisNanowire Synthesis
V
27 October 2006Slide 24 Turner and Northen
Gecko Gecko
‘Organorods’‘Organorods’
Courtesy Edward Arzt (S. Gorb)
E = 6 GPa
E = 1-15 GPa
27 October 2006Slide 25 Turner and Northen
Nanorod PropertiesNanorod Properties• Diameter ~ 200 nm• Length ~ 4 µm • Beta Keratin• Modulus ~ 1-15 GPa• High Density• No Condensation• Ultra-Hydrophobic,
Contact Angle ~170°
• Diameter ~ 200 nm• Length ~ 4 µm • Beta Keratin• Modulus ~ 1-15 GPa• High Density• No Condensation• Ultra-Hydrophobic,
Contact Angle ~170°
Courtesy Edward Arzt (S. Gorb)
27 October 2006Slide 26 Turner and Northen
Contact AngleContact Angle
Hydrophilic 42.5°-OR-
Highly Hydrophobic 145°
Hydrophilic 42.5°-OR-
Highly Hydrophobic 145°
27 October 2006Slide 27 Turner and Northen
Adhesion TestingAdhesion Testing
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0 500 1000 1500 2000
Displacement (nm)
adhesion
Northen, M. T., Turner, K.L. (2005). “Meso-scale adhesion testing of integrated micro-and nano-scale structures.” Sensors and Actuators A (In Press).
27 October 2006Slide 28 Turner and Northen
Slide 29
Adhesion Testing
Slide 30
Adhesion Comparison
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Applied Normal Pressure (Pa)
Adh
esio
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reng
th (P
a)
Slide 31
Durability Comparison
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Iteration
Adh
esio
n (P
a)
Slide 32
Solid vs. Flexible
Damage vs. No Damage
Slide 33
Mimicked?
Coutesy Eduard Arzt (S. Gorb)
Gecko > 300 Pa (Adhesion)
90 kPa (Frictional Adhesion)
Synthetic < 30 Pa (Adhesion)
μ’ = Fadhesion / Fpreload
Geim et. al μ’ = 0.06
Northen & Turner μ’ = 0.125
Gecko μ’ = 8-15
Adhesion Control
Slide 36
Controllable Conformance
Slide 37
Ferromagnet in a magnetic field
Slide 38
Michael-Fabricated Gecko-Fabricated
Slide 39
Active Area
Support Substrate
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Slide 45
Basalt II Adhesion Tester
Test surface
Glass flat punch, D = 5 mm
Spring
Laser interferometer
PiezoMicro positioning stage
Slide 46
Basalt II Adhesion Tester
Slide 47
Glass Flat Punch Glass Flat Punch
Slide 48
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0 20 40 60 80 100 120 140
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Pul
l-off
Forc
e (μ
N)
Adhesion off (magnetic field present)
Adhesion on (magnetic field absent)
Preload (μN)
Adhesion S
trength (Pa)
Contact Pressure (Pa)
μ’ = 1.5
Slide 51
Synthetic vs. Gecko
μ’ = 1.5 μ’ = 8-15Fadhesion < 15 Pa Fadhesion > 300 Pa
Slide 52
The future:
Frictional Adhesion (more bio-inspiration)
Increased Packing Density
Integrated Magnetic Fields
AcknowledgementsAcknowledgementsFunding by:
ARMY Institute for Collaborative BiotechnologyAFOSR Structural Mechanics Program
Collaborators:
Eduard Arzt, Max Planck Institut, Stuttgart, GermanyJacob Israelachivili, UCSB
Turner Lab: Laura Oropeza, Weibin Zhang, Michael Requa, Abhishek Srivastava, Kari Lukes, Benedikt Zeyen, Mark Zielke, Barry DeMartini
‘Dude’
Funding by:
ARMY Institute for Collaborative BiotechnologyAFOSR Structural Mechanics Program
Collaborators:
Eduard Arzt, Max Planck Institut, Stuttgart, GermanyJacob Israelachivili, UCSB
Turner Lab: Laura Oropeza, Weibin Zhang, Michael Requa, Abhishek Srivastava, Kari Lukes, Benedikt Zeyen, Mark Zielke, Barry DeMartini
‘Dude’
For More Information:
www.engr.ucsb.edu/~tmems