By Erika Eiser, Complex Fluids Group, UvAmsterdam

1. 30 November 2006 By Erika Eiser, Complex Fluids Group, UvAmsterdam Master Class Erika Eiser René Williams, & Jeroen Goedkoop

2. Nano-technologies inspired by Nature

3. Introduction The Lotus effect Photonic crystals By Erika Eiser, Complex Fluids Group, UvAmsterdam Quantum dots as bio-sensors

4. New Materials By Erika Eiser, Complex Fluids Group, UvAmsterdam The Lotus effect Nelumbo nucifera, the sacred lotus flower.

5. By Erika Eiser, Complex Fluids Group, UvAmsterdam Many plants show the phenomena that water droplets do not wet their leaves.

6. Wetting lv ls sv  By Erika Eiser, Complex Fluids Group, UvAmsterdam Surface tensions: vapor lv– liquid/vapor liquid ls– liquid/solid sv– solid/vapor solid Young’s equation

7. Wetting By Erika Eiser, Complex Fluids Group, UvAmsterdam poor wetting good wetting complete wetting  > 90°C 90° >  > 0°   0° lv lv lv ls sv    cos < 0 cos = 0 cos > 0

8. Wetting By Erika Eiser, Complex Fluids Group, UvAmsterdam Wetting is a physical property, purely driven by surface energies!!

9. There are 2 factors that render surfaces even more hydrophobic. • Surface roughness Sand blasted aluminum By Erika Eiser, Complex Fluids Group, UvAmsterdam • Surface ripples (bumps on the surface) http://www.botanik.uni-bonn.de/system/lotus/en/prinzip_html.html#das

10. Modifying the surface tension of a solid surface. vapor liquid * solid dx By Erika Eiser, Complex Fluids Group, UvAmsterdam Surface roughness: Only  180° can be reached! • amplifieswetting on hydrophilic surfaces • reduceswetting on hydrophobic surfaces

11. Hydrophobic solid surface can be made more hydrophobic: By Erika Eiser, Complex Fluids Group, UvAmsterdam The energy cost to wet a hydrophobic surface with water is larger than to “wet” the solid surface with air (sv < sl) The liquid drop will try to minimize its contact area with the solid, leaving air pockets underneath! J. Bico et al., Europhys. Lett., 47 (2), pp. 220-226 (1999) J. Bico et al. / Colloids and Surfaces A: Physicochem. Eng. Aspects 206 (2002) 42 41–46

12. Lotus Effect By Erika Eiser, Complex Fluids Group, UvAmsterdam Where is the connection to Nature?

13. Lotus Effect By Erika Eiser, Complex Fluids Group, UvAmsterdam Lotus leaves are known to be extremely hydrophobic and self-cleaning surfaces. http://www.botanik.uni-bonn.de/system/lotus/en/lotus_effect_multimedia.html

14. Lotus effect Viscous water-soluble glue simply rolls off the Lotus leave. By Erika Eiser, Complex Fluids Group, UvAmsterdam Oleophobic color that is used by the police to mark bank notes can be rinsed of from the surface.

15. Self cleaning action. By Erika Eiser, Complex Fluids Group, UvAmsterdam  > 150° http://www.botanik.uni-bonn.de/system/lotus/en/lotus_effect_multimedia.html

16. Applied Nano-Technology: Self-cleaning action. By Erika Eiser, Complex Fluids Group, UvAmsterdam We may create new self-cleaning paints or wallpaper. Facade paint, self-cleaning with rainfall thanks to the Lotus-effect® http://www.botanik.uni-bonn.de/system/lotus/en/lotus_effect_multimedia.html

17. Examples of Manmade Super-hydrophobic Surfaces. By Erika Eiser, Complex Fluids Group, UvAmsterdam Creating self-cleaning glass coatings. http://www.nano-products.info/nanotechnologie-autoscheiben-versiegelung.php

18. Examples of Manmade Super-hydrophobic Surfaces. F F – C – C – F F n = repeat unit By Erika Eiser, Complex Fluids Group, UvAmsterdam poly(tetrafluoroethylene) (PTFE) = non-wetting coating. Kenneth K. S. Lau et al. Nano Letters 2004

19. Modifying the surface tension of a solid surface. • Typical hydrophobic surfaces: polymers, hydrocarbons & fluorocarbon. Electron micrograph teflon, polyethylene, styrophor http://en.wikipedia.org/wiki/Gore-Tex By Erika Eiser, Complex Fluids Group, UvAmsterdam • High surface energy materials (typically hydrophilic): metals, glass, anodized Al http://solutions.3m.com/wps/portal/3M/en_US/VHB/Tapes/Product-Information/How-to-use/Design-Tape-Selection/

20. ANTHRAX By Erika Eiser, Complex Fluids Group, UvAmsterdam HIV GRIEP Self-Assembly

21. By Erika Eiser, Complex Fluids Group, UvAmsterdam The magic words that make the handling of nano-technology feasible are: “bottom-up approach” & self-assembly

22. Biological examples: By Erika Eiser, Complex Fluids Group, UvAmsterdam http://www.daviddarling.info/encyclopedia/V/virus.html

23. By Erika Eiser, Complex Fluids Group, UvAmsterdam Can we use self-assembly to make our own “smart” drugs?

24. By Erika Eiser, Complex Fluids Group, UvAmsterdam Surfactants = Surface Active Molecules = Amphiphiles • Surfactants are molecules with amphiphilic character. • This means the molecules consist of a hydrophobic (tail) and hydrophilic (head group) part. tail head group

25. Self-assembling soap molecules By Erika Eiser, Complex Fluids Group, UvAmsterdam http://www.nonequilibrium.com/complexfluids.htm

26. Our Research and what we are going to do today By Erika Eiser, Complex Fluids Group, UvAmsterdam Sodium dodecyl sulfate (SDS) Spontaneous self-assembly into wormlike micelles + Pentanol + Water http://www-its.chem.uva.nl/research/complex_fluids/

27. Our Research and what we are going to do today By Erika Eiser, Complex Fluids Group, UvAmsterdam Nano wires Drug design UvA (E.Eiser, A. Gaikward, P.Verschuren) • Physical questions: How do the clusters align? How do they influence the crystal growth?... • Chemistry/Nanotechnology: http://www-its.chem.uva.nl/research/complex_fluids/

28. By Erika Eiser, Complex Fluids Group, UvAmsterdam Self-Assembly of colloids

29. Natural Colloidal Crystal By Erika Eiser, Complex Fluids Group, UvAmsterdam

30. Bio-mineralization By Erika Eiser, Complex Fluids Group, UvAmsterdam Butterflies & Photonic Crystals

31. Bio-mineralization By Erika Eiser, Complex Fluids Group, UvAmsterdam Morpho

32. Photonic Band Gap By Erika Eiser, Complex Fluids Group, UvAmsterdam Photonic crystals: • Allow only a narrow band of visible light pass • All other wavelength will be blocked • Just like electrons in a semi-conductor.

33. Photonic Band Gap By Erika Eiser, Complex Fluids Group, UvAmsterdam Application: New, powerful lasers and optical fibers. http://policy.iop.org/v_production/v12.html

34. By Erika Eiser, Complex Fluids Group, UvAmsterdam The difficulty: Making photonic crystals with complex structures, e.g. the diamond structure. And many more problems will await you.

35. DNA By Erika Eiser, Complex Fluids Group, UvAmsterdam Self-Assembly For biomedical applications

36. By Erika Eiser, Complex Fluids Group, UvAmsterdam Quantum dots Nanometer sized semiconductors (CdSe) Dr. D. Talapin, University of Hamburg, http://www.chemie.uni-hamburg.de/pc/Weller/

37. By Erika Eiser, Complex Fluids Group, UvAmsterdam Quantum dots (QDs) nano-sized semiconductor crystals that, when stimulated by laser light, can fluoresce in a rainbow of colors for weeks at a time Nie and colleagues have succeeded in attaching quantum dots to peptides or antibodies that recognize specific cancer cells, and then using the dots to isolate individual cancerous areas (as in this mouse). X. Gao and S. Nie, Emory University School of Medicine

38. Summary By Erika Eiser, Complex Fluids Group, UvAmsterdam Nature has taught us: • Self-assembly is possible by • Using amphiphilic molecules like • Soaps, • Proteins with hydrophobic and hydrophilic patches

39. Thank you for coming & listening.