2063-17

ICTP/FANAS Conference on trends in Nanotribology

19 - 24 October 2009

Materials for reversible adhesion: from biological systems to wall-climbing robots

GORB Stanislav University of Kiel Zoological Institute Department for Functional Morphology and Biomechanics Am Botanischen Garten 1-9, 24098 Kiel Schleswig -Holstein Surfaces and Interfaces Goals

sensorics to understand to understand attachment functional evolutionary drag reduction principles to develop tendencies optics (anti-reflection) broad comparative grinding studies on methods studies anti-friction ultrastructure, material microscopy EVOLUTIONARY PROJECTS sound generation properties, techniques, respiration force range, measurements of to find interesting thermoregulation motion in stiffness, hardness, biological adhesion, friction at properties of systems coloration pattern systems local and global self-cleaning scales transfer of the natural design etc., etc.... solutions in the material science FUNCTIONAL PROJECTS Romalea microptera BIOMIMETCS PROJECTS

What Material Do We Want to Develop?

Sticky...

Do we want to use it for walking on the wall and ceiling?

...and extremely fast ...to unpredictable surfaces ...and fast releasable (millions of cycles) ...non-conglutinating! Autumn et al. 2000; 2002; 2006

Ceiling Situation (Static) Ceiling Situation

friction adhesion

weight

contact formationstrong adhesion contact breakage -fast -fast - reliable - minimal force - minimal load on the ceiling

1 Terrain structures for interlocking and friction enhancement on rough substrata -claws - stiff pointed hairs

structures for adhesion and friction enhancement on smooth substrata - pulvilli - arolia - euplantulae - etc, etc.

Two Designs of Attachment Pads Two Designs of Attachment Pads

Gorb and Beutel, 2001, Naturwissenschaften

Blattaria Diptera Coleoptera Plecoptera Megaloptera arolium present absent present in some species Hymenoptera Raphidioptera pulvilli smooth hairy smooth in some species Homoptera euplantulae present absent present in some species present absent Heteroptera hairy soles

Smooth Attachment System Material Design

Gorb et al., 2000, J. Comp. Physiol.

2 µm

2 µm 5 µm viridissima Tettigonia viridissima

2 Hairy Pads of Bioinspired Patterned Surfaces

Beutel and Gorb, 2001, J. Zool. Syst. Evol. Res. Sitti and Fearing 2002 Northen and Turner, 2005 Gorb, Peressadko et al. Glassmaker et al., 2004

Geim et al., 2003

Yurdumakan et al., 2005 Campolo, Jones, Fearing, 2003

A. Dobsonfly Sialis lutaria B. Priacma serrata C. Beetle Rhagonycha fulva D. Bibio nigriventris E. Fly Episyrphus balteatus F. Earwig Forficula auricularia G. Beetle fusca

Example of the Hairy Attachment Pad Secretory Fluid

motorics (arrangement of Fly Eristalis pertinax Reduviid bugs muscles) Edwards and Tarkanian, 1970 joint design, movements during contact formation and breakage Bauchhenss and Renner, sensorics 1977; Bauchhenss, 1979; Walker et al., 1985 material structure and properties forces and their Ishii, 1987; directionality Eisner and Aneshansley, 2000 contact mechanics A. Pulvillus of the syrphid fly Eristalis cl, claw pertinax in contact with the glass surface pul, pulvillus potential substrata B. Tenent setae tips surrounded by sc, secretion (profile, surface energy) 20 µm secretion ts, tenent setae fluid (chemical C. Footprints on a glass surface. Note the composition, viscosity, regular pattern of droplets transporting system)

Design of Adhesive Setae Microemulsion

Gorb, 1998, Proc. Roy. Soc. B Fy Calliphora vicina is adapted for the release of Gorb, 2001 adhesive substances close to the area of contact Carbon-Platinum replicas ? of the frozen footprints (black arrows indicate direction of coating)

SEM (A, D) TEM (B-C, E-G) A-F. Fresh prints G. Dry prints

dr, drops ns, nano-drops TEM and SEM micrographs of the two types of tenent setae in the syrphid fly Episyrphus balteatus. Setae of the type 2 (A, B) are located distally in the pulvillus, whereas setae of the type 1 (C, D) are located at the basis of the pulvillus. DL, dense layer; LU, lumen; PL, end plate.

3 AFM-Measurements of Attractive Forces Force Mapping of Single Setal Tip

Langer, Ruppersberg, Gorb, 2004, Proc. Roy. Soc. B Langer, Ruppersberg, Gorb, 2004, Proc. Roy. Soc. B

Fly Calliphora vicina cantilever deflection, nm

Z –displacement, nm

Range of Attractive Forces Dimension and Density of Setae

Langer, Ruppersberg, Gorb, 2004. Proc. Roy. Soc. B. Arzt, Gorb, Spolenak, 2003, PNAS

Setal density dependence on the body mass

Dependence of the hair density (terminal elements) of the attachment pads on the body mass in hairy pad systems of representatives from diverse animal groups

Experiment with the Structured Polymer Surface Prototypes

Peressadko and Gorb, 2004, J. Adhesion

4 Contact Shape Function of Terminal Elements

Spolenak, Gorb, Gao, Arzt, 2004, Proc. Roy. Soc. A Gekko gecko Persson and Gorb, 2003, J. Chem. Phys. TE of the A. Bug Pyrrhocoris apterus, beetle smooth pulvillus fastuosa in B. Tettigonia viridissima, surface of contact the attachment pad

C. Fly Myathropa florea, unspecialised hairs on the leg

D. Fly Calliphora vicina, seta of the pulvilli

E. Beetle Harmonia axyridis, seta of the second tarsal segment

F. Beetle Chrysolina fastuosa, thickness of 1 µm seta of the second tarsal segment terminal elements ranges G. Male beetle Dytiscus from 200 nm (in Functions: (1) Low bending stiffness of thin marginatus, suction terminal plates enables an intimate contact cups on the ventral side beetles) to 10-15 of the foreleg tarsi nm (in gecko) with surface irregularities. (2) Easy contact formation by sliding. (3) Increasing of contact forces without normal load

Spatula Contacts (Cryo-SEM) Slope

Gekko gecko

Fly α

LAMELLAE 200 µm Functions: (1) To decrease the bending stiffness of setae. (2) Spider To enhance adaptability of (data of S. Niederegger and P. Walther) single contacts. (3) Part of the built-in detachment mechanism 1 µm SETAE Gecko 20 µm

Hierarchy Detachment Movements in the Fly

Niederegger and Gorb, 2003, J. Insect Physiol. Insects puvlilli setae with spatulae

rotation twisting

Function: To enhance adaptability lamella setae spatulae shifting pulling of single contacts at roughness of different levels of magnitude (reflection of real fractal world) Gecko

5 2D Force Measurements on the Leg of the Freely-Walking Fly Pad Orientation

Gorb et al., 2007 SIX LEGGED THREE LEGGED

TWO LEGGED force, µN

Fly Calliphora vicina time, s beetle Chrysolina fastuosa, ceiling

Peeling of Two Sticky Tapes Peeling

the experiment Gorb et al., 2007 α=90° F Wb

Strong stress concentration in the crack. Force is only 800 proportional to the width of the 700 tape

600

500

400 α<90° F WA

mass, g mass, 300

200 Stress is distributed scheme of the animal on the ceiling over the large area. 100 No strong stress 0 concentration in the 30 50 70 90 crack. Force is proportional to the angle, ° area of the tape

Challenge: to put all this together Dry Adhesives

Gorb, Varenberg, Peressadko, Tuma, 2007, J. Roy. Soc. Interface α • dimension and density •aspectratio • slope • hierarchy • shape of the contact • asymmetry E 2 • proper movements (during attachment and detachment) stiffer • gradient materials 150 µm 20 µm softer • non-conglutination E 1 with Binder GmbH (Holzgerlingen, Germany)

6 Dry Adhesives Dry Adhesives

Gorb, Varenberg, Peressadko, Tuma, 2007, J. Roy. Soc. Interface BIOINSPIRED FUNCTION FEATURES increase of the total perimeter of contact contact prevention of the subdivision crack propagation • BK, backing • DP, dust tolerance to the contamination particle hexagonal the highest packaging • LP, lip at the pattern density of structures margin of the pillar tip • NR, narrowing thin plate-like tolerance to of the pillar the contamination head close to the tip prevention of the • PL, pillars joint-like crack propagation • SH, shaft neck adaptability to uneven surfaces high aspect decrease of stored ratio elastic energy

Properties of Dry Adhesives Contamination of Dry Adhesives

Gorb, Varenberg, Peressadko, Tuma, 2007, J. Roy. Soc. Interface Gorb, Varenberg, Peressadko, Tuma, 2007, J. Roy. Soc. Interface

×11 ×6 tenacity, KPa

Wall Walking Using Dry Adhesives Wall Walking Using "Dry Adhesives"

Daltorio et al. 2004, IROS Conference Niederegger and Gorb, 2003. J. Insect Physiol. Daltorio et al., 2005, CLAWAR Conference

together with Quinn Lab (Daltorio, Horchler, Ritzmann, Quinn), Case Western Reserve with Daltorio, Horchler, Ritzmann, Quinn University, Cleveland, OH, USA Case Western Reserve University, Cleveland, OH, USA

7 Roughness Effects on Hairy Pad Attachment Plant Surfaces

25 Gorb and Peressadko, 2004, Bionik Gorb and Gorb, 2002, A Entomol. Exp. Appl. Gastrophysa viridula 20

15 SMOOTH STRUCTURED

10 not structured trichomes F structured lateral force, mN lateral 5 Critical range wax layers of roughness wax layers 0 N=5, n=50 01 3 5791113 35 30 dry dry 25 hairy felt-like SEM B 20 15 10 5

profile lateral force, mN 0 1 µm 800 µm C 0 0.3 1 39 12

particle diameter, µm particle diameter, µm

Pruinose Plant Surfaces Group www.flyfoot.de

Post docs: Elena Gorb Alexander Kovalev Jan Michels Katja Steffen Dagmar Voigt

Lactuca serriola Chelidonium majus Robinia pseudoacacia Chenopodium album PhD students: (leaf, lower) (leaf, lower) (leaf, upper) (leaf, upper) Martina Benz Philipp Bußhardt Marie-Christin Klein Henrik Peisker

Technicians: Support: Astrid Ingwersen Federal Ministry of Education and Research Joachim Ösert German Science Foundation Brassica oleracea Acer negundo Prunus domestica Alexander von Humboldt Foundation (leaf, lower) (stem) (fruit) Schlößmann Foundation Foundation of Baden Württemberg

8