SOFT CONDENSED MATTER COMPLEX MOLECULES AT MESOSCOPIC SCALES

1. eman ta zabal zazu UPV/EHU SOFT CONDENSED MATTERCOMPLEX MOLECULESAT MESOSCOPIC SCALES Juan Colmenero Departamento de Física de MaterialesUPV/EHU Unidad de Física de Materiales CSIC-UPV/EHU Donostia International Physics Center

2. Why Neutrons? Past & Present: Key Neutron Scattering Contributions to Soft Matter What is Soft Condensed Matter? Neutron Scattering & Soft Matter SOFT CONDENSED MATTERCOMPLEX MOLECULESAT MESOSCOPIC SCALES

3. What is Soft Condensed Matter? Neutron Scattering & Soft Matter Future: ESSNew Opportunities for Soft Matter SOFT CONDENSED MATTERCOMPLEX MOLECULESAT MESOSCOPIC SCALES

4. What is Soft Condensed Matter?

5. Soft Condensed Matter The concept of “soft matter” subsumes a large class of molecular materials: Polymers Thermotropic liquid crystals Micellar solutions Microemulsions Colloidal suspensions Substances in biology: membranes, vesicles,… ...

6. Soft Condensed Matter Wide range of Applications: Structural and packaging materials Foams and adhesives Detergents and cosmetics Paints Food additives Lubricants and fuel additives Rubber in tires ...

7. common physicochemical causes large number of internal degrees of freedom weak interaction between the structural units delicate balance entropicenthalpic contrib. to free energy entropy enthalpy (( (( (( (( (( (( (( (( (( (( (( (( (( (( (( (( (( (( (( Soft Condensed Matter very different properties

8. SURFACTANTS MICELLAR SOLUTIONSAMPHIPHILICS POLYMER POLYMER SURFACTANTS MICELLAR SOLUTIONSAMPHIPHILICS BIOLOGICAL SYSTEMS LIQUID CRYSTALS LIQUID CRYSTALS MEMBRANES MEMBRANES BIOLOGICAL SYSTEMS Soft Condensed Matter Structural units: large molecules or aggregates of molecules Different length scales: different structural & dynamical properties

9. MACROMOLECULES Repetition of NMonomers • H • H • H • C • C • C • C • H • H • C • H • H • H POLYMER

10. ATOMIC STRUCTURE “RANDOM COIL” STRUCTURE ≈ 25Å ≈ 300Å POLYMER

11. P(Q) 1 ms 1000 Å 0.01 0.1 1 Q(Å-1) GLASSY BEHAVIOUR Intermolecular Range a - Relaxation Length scale Time scale S(Q) Molecular Length Scale Vibrations Side Groups b - Relaxation ... 1 2 0 Q(Å-1) 1 Å 1 ps H H C H C O C H H H Static Polymers Dynamics Large Scale Dynamics Chain Diffusion Reptation Rouse Dynamics... 3

12. Timescales 1 ms logt(s) end to-end (Mw) 0 Ea ≈ 0.5eV a -5 b Time scale Ea ≈ 0.1eV CH3 -10 1/T 1/Tg Molecular Length Scale Vibrations Side Groups b - Relaxation ... 1 ps H H C H C O C H H H Polymers Dynamics Large Scale Dynamics Chain Diffusion Reptation Rouse Dynamics... GLASSY BEHAVIOUR Intermolecular Range a - Relaxation

13. Neutrons & Soft Matter Why Neutrons?

14. Suitability of length and time scales accessed, especially SANS Q Q Q Q Neutrons & Soft MatterUnique role:

15. Suitability of length and time scales accessed, especially SANS Decipher structure & dynamics in complex systems Selectivity varying contrast: HD bH=-3.74 fm bD=+6.67 fm Neutrons & Soft MatterUnique role:

16. Suitability of length and time scales accessed, especially SANS Decipher structure & dynamics in complex systems Selectivity varying contrast: HD Unique role of neutron reflectometry Surface and interfaces in soft matter Neutrons & Soft MatterUnique role:

17. Suitability of length and time scales accessed, especially SANS Decipher structure & dynamics in complex systems Selectivity varying contrast: HD Unique role of neutron reflectometry Surface and interfaces in soft matter High penetration: Influence of external fields/parameters e.g. Fabrication conditions Space-time resolution Molecular motions Viscoelastic/mechanical properties Tailor made materials Neutrons & Soft MatterUnique role:

18. Neutrons & Soft Matter Techniques

19. Large Scale Dynamics Chain Diffusion Reptation Rouse Dynamics... P(Q) 1 ms 1000 Å 0.01 0.1 1 Q(Å-1) Intermolecular Range a - Relaxation Length scale Time scale S(Q) Molecular Length Scale Vibrations Side Groups b - Relaxation ... 3 1 2 0 Q(Å-1) 1 Å 1 ps H H C H C O C H H H NEUTRON SCATTERING TECHNIQUES NSE SANS WA-NSE BS TOF Liquid Diffractometer Polarised Diffuse Scattering

20. 1 ms 1000 Å Length scale Time scale 1 Å 1 ps NEUTRON SCATTERING TECHNIQUES Complex Materials: Interfaces NSE SANS Reflectometry WA-NSE BS TOF Liquid Diffractometer Polarised Diffuse Scattering

21. Neutrons & Soft Matter Past and Present: Key Contributions (some examples)

22. Conformation of Polymer Chains in the Melt and the Amorphous State

23. Re Rg Conformation of Polymer Chains in the Melt and the Amorphous State “Random Coil Model” Flory 50’s First experimental evidences by neutron scattering (70’s) Kirste et al., Jülich Benoit et al., Grenoble

24. SANS Conformation of Polymer Chains in the Melt and the Amorphous State

25. 2 P(Q) = [ Q2<Rg2>- 1 + e(-Q2<Rg2>) ] Q4<Rg2>2 PMMA Kirste et al. (1975) Conformation of Polymer Chains in the Melt and the Amorphous State

26. 2 <Rg > µ MW PS Benoit et al. (1974) Conformation of Polymer Chains in the Melt and the Amorphous State

27. Linear Chain Dynamics in the Melt

28. Gaussian Chain in a Heat Bath N l fn(t) n Entropic springs z Linear Chain Dynamics in the Melt Rouse Model

29. NSE Linear Chain Dynamics in the Melt Rouse Model Diffusion t Rouse log <r2(t)> t1/2 log t

30. Long time plateaus NSE Increasing Molecular Weight Mw Spatial Confinement Entanglements Linear Chain Dynamics in the Melt REPTATION Rouse Model

31. M. Monkenbusch et al. (unpublished) Jülich Diffusion t t Diffusion log <r2(t)> Rouse t1/2 t1/2 Reptation t1/4 Local Reptation te log t tR td Linear Chain Dynamics in the Melt Reptation Model (Edwards, deGennes) Rouse Model

32. Dynamics in Miscible Polymer Blends

33. logt 100% 50/50 100% 1/T Dynamics in Miscible Polymer Blends “DYNAMIC HETEROGENEITY” Different segmental dynamics (a-relaxation) for each component in the blend

34. PVE 100% Blend PVE/PI 50/50 PI 100% Dynamics in Miscible Polymer Blends “DYNAMIC HETEROGENEITY” Dielectric Spectroscopy

35. PI 100% inblend: PI & PVE Instrumental resolution PVE 100% Dynamics in Miscible Polymer Blends “DYNAMIC HETEROGENEITY” Quasielastic Neutron Scattering Q: 0.3 ... 2 Å-1 (Backscattering)

36. Crossover at ~ lK PVE 100% Homogeneous Heterogeneous 1/Q~lK PI 100% Dynamics in Miscible Polymer Blends Is there any relevant length scale for miscibility? Q-dependence of the characteristic relaxation time NEUTRON SCATTERING PRL 85, 772 (2000) PVE & blend PI

37. Future Opportunities

38. “Scientific and Technological development is unpredictable” (by definition) Future Trends in Soft Matter E.g., “Heavier-than-air flying machines are impossible” Lord Kelvin, president, Royal Society, 1895 “I think there is a world market for maybe five computers” Thomas Watson, chairman of IBM, 1943 “640K ought to be enough for anybody” Bill Gates, 1981 but ...

39. Future Trends in Soft Matter Multi-component soft & soft/hard materials tailor made for industrial applications Increasing structural & dynamical complexity at different length and time scales

40. In situ real time kinetic & non equilibrium processes Experiments on inherently small or dilute samples Smaller cross-sections Measurements over shorter times Future Trends in Soft Matter Increasing structural & dynamical complexity at different length and time scales

41. Advanced Chemistry Computer Simulations and Modellisation Neutron Scattering: decisive role ... in combination with Current limitation: INTENSITY

42. more intensity at the detector higher resolution in frequency Fourier time and real time Neutron Scattering: decisive role How can the ESS further contribute to the development?

43. Instrument Total gain High intensity SANS ~ 100 High intensity reflectometer ~ 40 Liquids diffractometer ~ 20 Polarised diffuse scattering ~ 300 High resolution NSE ~100 Wide angle NSE ~ 300 Backscattering ~ 50 Variable chopper cold TOF ~ 800 Structure Dynamics ESSContribution Performance gain factor calculated for Soft Matter instruments:

44. In situ real time kinetic & non equilibrium processes Experiments on inherently small or dilute samples Smaller cross-sections Measurements over shorter times Future Trends in Soft Matter Increasing structural & dynamical complexity at different length and time scales

45. In situ real time kinetic & non equilibrium processes Experiments on inherently small or dilute samples ESS HIGH INTENSITY Smaller cross-sections Measurements over shorter times Future Trends in Soft Matter

46. In situ real time kinetic & non equilibrium processes Experiments on inherently small or dilute samples ESS HIGH INTENSITY Smaller cross-sections Measurements over shorter times New Opportunities for Soft Matter

47. SANS Mixing t=0 + t ALWAYS INTENSITY LIMITED Kinetic studies Recent example: Micellar exchange kinetics

48. Real time: exchange kinetics unexpected result: two exchange mechanisms ALWAYS INTENSITY LIMITED Kinetic studies Recent example: Micellar exchange kinetics

49. ALWAYS INTENSITY LIMITED Kinetic studies Recent example: Micellar exchange kinetics Fast Process: unimer exchange Slow Process:???

50. +n M Bu-Li++ M →Bu-M-Li+→Bu-(M)n-M-Li+↔[Bu-(M)n- M-Li+]x=? Initiation Chain Growth to high vacuum line Polymerisation reactor 0 . 8 1 1 0 t = 0 m i n . 0 . 6 t = 3 0 m i n . t = 6 5 m i n 0 1 0 t = 6 9 h i n i t i a t o r I raw[cm-1] (dS/dW)(Q)[cm-1] t = 4 2 h t = 3 0 h 0 . 4 t = 2 1 h t = 1 4 h - 1 1 0 t = 1 0 h t = 7 h 0 . 2 t = 3 h t = 1 h t = 1 2 m i n . - 2 1 0 0 . 0 0 . 0 0 0 . 0 1 0 . 0 2 0 . 0 3 0 . 0 4 Maximal aggregation after initiation - 3 - 2 - 1 Chain growth during complete reaction 3 x 1 0 1 0 1 0 Q[Å-1] Q[Å-1] Observed chain aggregation (x > 12) contradicts common picture of polymerisation mechanism light scattering sample SANS sample ALWAYS INTENSITY LIMITED Kinetic studies Recent example: In Situ polymerisation