1. Self Healing : an alternative strategy to make materials perform better July 14, 2011 Sybrand van der Zwaag Faculty of Aerospace Engineering TU Delft Booosting 2008 Rotterdam

2. Material development over 120 centuries July 14, 2011 After M.F. Ashby

5. More lessons from nature July 14, 2011

6. July 14, 2011 Assuring a dynamic equilibrium in bone 50 µm Cells to remove material Cells to create material Cells to sense the stress- state

7. July 14, 2011 Cell activity during remodelling control parameter: P = cell activity OC OB OC > OB Bone mass  P  OB > OC Bone mass  P  set point

9. Self Healing ambitions (single event) July 14, 2011 Time Performance original improvement SH coating

10. Self healing ambitions (multiple healing) July 14, 2011 Time Performance original improvement SH coating

11. Self healing ambition : massive and small scale damage July 14, 2011 Time Performance original improvement SH coating

14. Self healing in building materials July 14, 2011 Victor Li (2005)

16. Metal-like Behavior of Engineered Cementitious Compound July 14, 2011  cu ~ 4% Victor Li, Michigan, USA 0 1 2 3 4 0 1 2 3 4 5 6 Crack Width (  m) S t r e s s Stress (MPa) 0 2 0 4 0 6 0 8 0 1 0 0 C r a c k w i d t h Strain (%) 20 mm Damage

17. Self-Healed ECC Specimens July 14, 2011 Before Self-Healing After Self-Healing w ~ 60  m  = 1.5% Formation of CaCO 3 3 mm 3 mm

18. Mihara Bridge in Hokkaido, 2004 July 14, 2011 Cable Stayed Bridge Hokkaido, Japan Completed: Oct., 2004 Open to traffic: April, 2005 Length: 1000 m, span: 340 m Deck area: 20,000 sq. m.; ECC layer thickness: 38 mm Composite ECC-Steel Deck ECC used for stiffening deck & decrease stress in deck steel FRP shear key applied Weight reduction 40% Cost reduction: 50% Expected service life: 100 yrs

19. Self Healing bridge in Amsterdam July 14, 2011 van Hees, TUD

20. Bacteria Stimulated Crack Healing in Concrete July 14, 2011 H.M. Jonkers, Microlab, TU Delft

21. Alkaliphilic Endospore Bacteria July 14, 2011 Endospores

22. July 14, 2011 Goal: - Self-healing (blocking / plugging) of cracks results in more durable concrete - Use bacteria that produce bio-minerals (e.g. calcite) Methods: - Create right conditions for bacteria to 1. survive concrete environment for long time 2. produce calcite upon water ingression through cracks - Characterize self-healing of cracks: 1. type of material deposited 2. blocking characteristics 3. (regained) mechanical properties

23. Bacterial formation of CaC03 crystals on concrete fracture surfaces July 14, 2011 Zonder Met bacteri ën CaCO 3 -kristallen Jonkers, TU Delft

24. July 14, 2011 Preferred concrete properties: 7. Self-healing! Impregnation techniques to image the effect of healing

25. July 14, 2011 Why self-healing concrete? The Corrosion Society (USA) estimates the annual direct cost of corrosion in construction and other applications to be $276 billion . Longer service life, less maintenance: saves money and the environment

26. Self healing in coatings July 14, 2011

27. Polymer coating structure July 14, 2011 topcoat basecoat primer substrate

28. Maintaining Performance in natural materials July 14, 2011

29. Human Skin detail July 14, 2011

30. Self healing via a liquid agent July 14, 2011 “ The Scott White concept”

31. The Scott White approach July 14, 2011 = epoxy = liquid adhesive capsule = catalyst S.R. White et al, Nature 2002

32. Just cracked July 14, 2011

33. 5 seconds later July 14, 2011

34. 1 minute later July 14, 2011 = crosslinking adhesive

35. 45 minutes later July 14, 2011 = fully crosslinked adhesive

36. Self-Healing Epoxy July 14, 2011  = 90.3% 2.5 wt% Grubbs catalyst 5 wt% microcapsules Healing conditions: room temperature, 48 h

39. Coating on Micro vascular substrate July 14, 2011 Kathleen S. Toohey, Nancy R. Sottos, Jennifer A. Lewis, Jeffrey S. Moore & Scott R. White Nature Materials 6 , 581 - 585 (2007)

40. Molecular Approach to Self Healing in coatings July 14, 2011

41. Molecular processes in reversible networks (Diels –Alder reactions) July 14, 2011 +

42. Self healing coatings based on hydrogen bonding July 14, 2011

43. The future is nearer than you may think July 14, 2011