Photopolymerization of LC networks as
Ph t     l     i ti    f      t   k
  tool for micro- and nanostructuring
          ...
Functional polymers towards medical and
  cleantech
   l   t h
                                            • biosensors   ...
Soft Actuators
Courtesy: http://plantsinmotion.bio.indiana.edu




      phototropism in sunflower                        ...
Soft Actuators
  •     Actuating elements, e.g. in microfluidic devices, μ-pumps,
        mixers, valves
  •     (Bio) sen...
Electrostatic actuation of integrated artificial cilia
                                g




Jaap den Toonder, Hans Wilder...
Fabrication of electrostatic elements
                 800 μm            100 μm




      glass (embedded electrodes not s...
Photopolymerization of self-organizing reactive
liquid crystals
                                                          ...
± 25 yrs experience: LC networks are presently used to
improve LCDs on viewing angle, contrast and brightness
            ...
Liquid Crystal Actuators
                                O
                                                               ...
Thermal actuation splayed LC network
                                                                                     ...
UV light driven
        parallel to uniaxial orientation




                        UV        VIS
    perpendicular to un...
Liquid crystal network UV-actuator
     q      y
   Specific internal work comparison

                                   ...
Optimized X-link density for fast response

                                                                              ...
Bending also possible in uniaxial LC networks
 with gradient i UV i t
  ith    di t in    intensity
                      ...
Back bending of uniaxial films in UV
   gradient films
 • time delayed azo response
 • photobleaching




 • bending depen...
Device integrated photoresponsive elements:
       • structured by inkjet technology
       • multi-color responsive eleme...
Next steps at TU/e group

  Reverse function and
  employ microstructures f energy harvesting:
     l     i    t t      fo...
Reduction of order parameter + gradients in director
profile  driving force for geometry changes




 Mechanisms for Order...
Anisotropic hydrogels: H-bridged LC networks

                                                             O    HO        ...
Anisotropic hydrogels: H-bridged LC networks

                           OBA n = 3,5,6 (1:1:1)




                       ...
Anisotropic swelling in alkaline buffer solution
                                   O         HO                     OH-  ...
Chemical Actuation – pH

                                                                 • Twisted configuration
        ...
Activate by KOH dip – deactivate in acetic acid

                                                                         ...
Application of a hydrogel soft actuator: Wrapping of
eukaryotic cells

                                                   ...
Smectic hydrogen-bridged networks towards
nano-channels
      h     l
                                                    ...
X-linked smectic hydrogen-bridged LC networks
                 hydrogen-
                O
                               ...
X-linked smectic hydrogen-bridged LC networks
                 hydrogen-
                                                 ...
Covalent X-link bridges conserve order
         X-
during heat cycling
                                                   ...
Covalent X-link bridges conserve order
         X-
during heat cycling
                                                   ...
Breaking the H-bridges at high pH
             H-
                                                                        ...
Breaking the H-bridges at high pH
             H-
                                                                        ...
Opening of the network at high pH
                                                                                    NH4+...
Opening of the network at high pH
                                                                                        ...
Filling the ion channels with Ba2+




Philips Research Laboratories, D.J.Broer, Date(in numbers)
                        ...
Insertion of dipyridines in monomeric state
influences the pore sizes
 Forms a stable smectic complex:
                   ...
Applications being studied

                                                                          easy integration in
...
Summary
•      Engineering toolbox for top down/bottom up polymer network structuring

•      Top down: lithography/hologr...
With thanks to:
 The PICT group at TU/e                                                                The Biomolecular En...
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Icam 2009 Soft Actuators H Bridges Nanopores

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Icam 2009 Soft Actuators H Bridges Nanopores

  1. 1. Photopolymerization of LC networks as Ph t l i ti f t k tool for micro- and nanostructuring micro Towards Soft Actuators & Nanoporous Membranes Dirk J. Broer, C.W.M. Bastiaansen, C.L. van Oosten, K. D. Harris, J. Lub, C. K D Harris J Lub C Luengo Gonzalez Eindhoven University of Technology Philips Research Laboratories
  2. 2. Functional polymers towards medical and cleantech l t h • biosensors • regenerative medicine • μ-fluidics fluidics • triggered scaffolds • MEMS • fiber technology membranes b responsive materials Nano- Nano-medicine Water treatment Energy / light management • purification ifi ti • light capturing & guiding • targeted filtering • sun tracking • electro dialysis • reverse electrodialysis • (blue energy) Clean Technologies self- self-organized micro- and nano features micro- Philips Research Laboratories, D.J.Broer, Date(in numbers)
  3. 3. Soft Actuators Courtesy: http://plantsinmotion.bio.indiana.edu phototropism in sunflower phototropism in plastic Courtesy: Nikon Microscopy /Digital Video Gallery cilia motion in paramecium cilia motion in plastic Philips Research Laboratories, D.J.Broer, Date(in numbers)
  4. 4. Soft Actuators • Actuating elements, e.g. in microfluidic devices, μ-pumps, mixers, valves • (Bio) sensors & controlled drugs release • Artificial muscles / robotics • Regenerative medicine • Energy harvesting and sun tracking What is needed ? • Responsive molecules • Miniaturize structures down to μm level • Integrate into devices • Improve on motion figures, e g as inspired by micro organisms e.g. micro-organisms Philips Research Laboratories, D.J.Broer, Date(in numbers)
  5. 5. Electrostatic actuation of integrated artificial cilia g Jaap den Toonder, Hans Wilderbeek, Titie Mol, Murray Gillies, Judith de Goede, Wim Talen Philips Research Laboratories, D.J.Broer, Date(in numbers)
  6. 6. Fabrication of electrostatic elements 800 μm 100 μm glass (embedded electrodes not shown) develop acrylate in alkaline solution + patterned Al (100 nm) add 10 nm chromium layer etch Cr in cerium ammonium nitrate add 10 μm acrylate mix etch Al in phosphoric acid photopolymerized through mask CH3 O CH3 CH2 C n O C C CH2 C O CH2 O CH3 O CH3 CH2 C CH2 O C C CH2 CH2 CH2 induced stresses make the elements curl O C C CH2 Philips Research Laboratories, D.J.Broer, Date(in numbers) O CH3 Christiane de Witz, Thijs Bel
  7. 7. Photopolymerization of self-organizing reactive liquid crystals liquid crystal with reactive end groups O O O O O O O O O O hν bottom-up / top-down nano/micro structuring aligned LC monomer Philips Research Laboratories, D.J.Broer, Date(in numbers)
  8. 8. ± 25 yrs experience: LC networks are presently used to improve LCDs on viewing angle, contrast and brightness angle hν based on solid coatings and thin films with anisotropic optical properties e.g. Δn = n// - n⊥= 0.05 to 0.25 Philips Research Laboratories, D.J.Broer, Date(in numbers)
  9. 9. Liquid Crystal Actuators O O O O O O O O O O hν LC networks • Can be patterned, e.g. by lithographic means • Can be made responsive by orientation gradients • High modulus - 1GPa • Large work potential! despite small deformations ~ 2% Philips Research Laboratories, D.J.Broer, Date(in numbers)
  10. 10. Thermal actuation splayed LC network poly(C3M) / 60 μm αe contraction expansion αo 500 400 300 αo 200 α (ppm.K-1) 100 0 100 -100 -200 αe -300 200 250 300 350 400 450 T (K) Philips Research Laboratories, D.J.Broer, Date(in numbers) Titie Mol
  11. 11. UV light driven parallel to uniaxial orientation UV VIS perpendicular to uniaxial orientation E Z E contraction Z expansion Ken Harris, Casper van Oosten Philips Research Laboratories, D.J.Broer, Date(in numbers)
  12. 12. Liquid crystal network UV-actuator q y Specific internal work comparison Modulus Work density* Actuator comparison Strain (MPa) (kJ/m3) LC network UV actuator 1,5% 1000 56 1 LC elastomer UV actuator 13% 1 4 2 Thermal LC elastomer 50% 1 50 2 Skeletal Muscle 20% 40 80 *W = ¼ ε2E 1. M. Camacho-Lopez et al., Nat. Mater., vol. 3, 2004, 307-310 2. 2 J.Madden al., J. J Madden et al J Of Oceanic Eng 29 (3) July 2004 706-728 Eng., (3), 2004, 706 728 Casper van Oosten Philips Research Laboratories, D.J.Broer, Date(in numbers)
  13. 13. Optimized X-link density for fast response UV 0s 8s 16 s 24 s 32 s VIS 0s 4s 8s 12 s 20 s poly(5.5wt-%A6MA/C6M) O H2C O (CH2)6 O O + 48% O (CH2)5 CH3 O 0s 0.08 s 0.16 s 0.24 s 0.32 s Ken Harris, Casper van Oosten Philips Research Laboratories, D.J.Broer, Date(in numbers)
  14. 14. Bending also possible in uniaxial LC networks with gradient i UV i t ith di t in intensity it gradient in deformation gradient in UV intensity Light tracking Tabiryan Under study: Beam Engineering efficient light harvesting Bunning group, Air Force for solar energy? Lab Dayton, USA O ti Express, 2005 13 7442 Optics E 2005, 13, Philips Research Laboratories, D.J.Broer, Date(in numbers)
  15. 15. Back bending of uniaxial films in UV gradient films • time delayed azo response • photobleaching • bending depends on X-link Acknowledge Mark Warner density • X-link gradient by X link polymerization-induced diffusion UV light Side Sid A Fast reacting molecules Intensity gradient Slower reacting molecules Substrate Side B Philips Research Laboratories, D.J.Broer, Date(in numbers)
  16. 16. Device integrated photoresponsive elements: • structured by inkjet technology • multi-color responsive elements multi- 160 140 contraction 120 100 Angle 80 (degr) 60 40 20 expansion p 0 0 500 1000 1500 2000 I (mW/cm2) Casper van Oosten Philips Research Laboratories, D.J.Broer, Date(in numbers)
  17. 17. Next steps at TU/e group Reverse function and employ microstructures f energy harvesting: l i t t for h ti E.g. • polymer flaps with oriented dipoles (ferroelectrics) • electrodes top and bottom Energy from: • breeze • motion (vibration e.g. in building) • sound First estimates: 0.1 to 10 W.m-2 large area technologies Philips Research Laboratories, D.J.Broer, Date(in numbers)
  18. 18. Reduction of order parameter + gradients in director profile driving force for geometry changes Mechanisms for Order Reduction / triggers – Temperature variation – Breaking order by isomerization under radiation – Breaking chemical bonds, chemical reactions (pH) – Solvent swelling/deswelling Ken Harris, Casper van Oosten Philips Research Laboratories, D.J.Broer, Date(in numbers)
  19. 19. Anisotropic hydrogels: H-bridged LC networks O HO O O O O O O OH O L. Strezelecki, L. Liebert, Bull. Soc. Chim. France, 597 (1973) & 605 (1973) hν Cr 92 SmA 110 I Ken Harris, Casper van Oosten Philips Research Laboratories, D.J.Broer, Date(in numbers)
  20. 20. Anisotropic hydrogels: H-bridged LC networks OBA n = 3,5,6 (1:1:1) C6M 140 120 hν 100 Temperatu ( C) o 80 70 -105 oC processing window ure 60 Nematic N ti 12 wt% C6M // 40 Smectic 20 Cryst 0 Cryst ⊥ -20 0 20 40 60 80 100 Composition (wt% C6M) Ken Harris, Casper van Oosten Philips Research Laboratories, D.J.Broer, Date(in numbers)
  21. 21. Anisotropic swelling in alkaline buffer solution O HO OH- O O- OH O H+ O- O L⊥ L// %) ansion (% ΔL ⊥ ΔL // > L⊥ L // L⊥+ΔL Expa ⊥ Time (min) Ti ( i ) L//+ΔL// Ken Harris, Casper van Oosten Philips Research Laboratories, D.J.Broer, Date(in numbers)
  22. 22. Chemical Actuation – pH • Twisted configuration g • poly(nOBA/12%C6M) • 18μm thick • pH controlled with NaOH and acetic acid slow expansion fast expansion • Motion occurs over limited pH range at pH~11 • Deformation i reversible D f ti is ibl Ken Harris, Casper van Oosten Philips Research Laboratories, D.J.Broer, Date(in numbers)
  23. 23. Activate by KOH dip – deactivate in acetic acid polymer chains L activate deactivateo base acid Challenges: • water driven motor (with Peter Palffy-Muhoray) • (bio) molecular recognition: -NH2, CO2, O2 together with Sijbesma -TU/e uptake of agent molecules Lt Ken Harris, Casper van Oosten Philips Research Laboratories, D.J.Broer, Date(in numbers)
  24. 24. Application of a hydrogel soft actuator: Wrapping of eukaryotic cells Objectives: • To develop cell delivery technique • Potential to combine different cell population Status: • Experiments withA 431, human withA-431, carcinoma epidermoid cells 37 25 oC 25 37 oC Sara Pedrón-Haba, Emiel Peeters, Philips Research Laboratories, D.J.Broer, Date(in numbers)
  25. 25. Smectic hydrogen-bridged networks towards nano-channels h l OBA n = 3 5 6 (1:1:1) 3,5,6 C6M 140 120 100 Temperatu (oC) 80 ure 60 Nematic N ti 40 Smectic 20 Cryst 0 Cryst -20 0 20 40 60 80 100 Composition (wt% C6M) Carmen Luengo Philips Research Laboratories, D.J.Broer, Date(in numbers)
  26. 26. X-linked smectic hydrogen-bridged LC networks hydrogen- O O HO ~19 Å O O O O O OH O O O O O ~42 Å 42 O O O O O O monomer / 104oC polymer / 104oC polymer / RT hν h cool polymerization down 26Å 27Å Å 43Å 30Å 31Å Carmen Luengo Philips Research Laboratories, D.J.Broer, Date(in numbers)
  27. 27. X-linked smectic hydrogen-bridged LC networks hydrogen- O HO O O O O O O OH O O O O O O O O O O O 0.50 ν H-bridges (C=O) only H bridges / RT sorbance 0.40 H-bonded ν (C=O) δ (C=C) 0.30 acrylate Abs 0.20 0.10 0.00 0 00 1900 1850 1800 1750 1700 1650 1600 1550 1500 1450 1400 1350 1300 Wavenumber O free C hν OH would have ν(C=O) ( ) at ~ 1730 cm-1 Carmen Luengo Philips Research Laboratories, D.J.Broer, Date(in numbers)
  28. 28. Covalent X-link bridges conserve order X- during heat cycling O HO Δ Δ O HO OH O OH O linear / RT linear / >200oC linear / RT heat cool linear X-linked (10w%) / RT X-linked / >200oC X-linked / RT X-linked X linked heat cool O O O O O O O O O O Conclusion: Alignment is recovered by presence of covalent X-links Philips Research Laboratories, D.J.Broer, Date(in numbers)
  29. 29. Covalent X-link bridges conserve order X- during heat cycling O HO Δ Δ O HO OH O OH O 600 500 400 Birefringence: Δ dΔ n 300 planar oriented samples between rubbed polyimide 200 glass plates 100 0 0 50 100 150 200 250 o Temperature ( C) Carmen Luengo Philips Research Laboratories, D.J.Broer, Date(in numbers)
  30. 30. Breaking the H-bridges at high pH H- NH4+ O HO NH44OH NH OH O O- OH O H++ H O- NH + O 4 0.14 184-10% om 079h eotropicfilm on w ou solu -am ia, ith t tion 0.45 184-10% om 079h eotropicfilm on after addin solu -am ia, g tion symmetric CO2 Antisymmetric CO2 1382.1 0.40 1675.6 0.12 0.35 0.10 0.30 1531.8 Absorbance Absorbance 0.08 0.25 0.20 0.06 0.15 0.04 0.10 0.02 0.05 005 1900 1850 1800 1750 1700 1650 1600 1550 1500 1450 1400 1350 1300 1 1900 1850 1800 1750 1700 1650 1600 1550 1500 1450 1400 1350 1300 1 W enum av ber W enum av ber • Hi h order of th l High d f the layers • Reduced order within the layer Carmen Luengo Philips Research Laboratories, D.J.Broer, Date(in numbers)
  31. 31. Breaking the H-bridges at high pH H- NH4+ O HO NH44OH NH OH O O- OH O H++ H O- NH + O 4 27Å NH4OH 31Å 34Å • Hi h order of th l High d f the layers • Reduced order within the layer Carmen Luengo Philips Research Laboratories, D.J.Broer, Date(in numbers)
  32. 32. Opening of the network at high pH NH4+ O HO NH44OH NH OH O O- OH O H++ H O- NH + O 4 27Å NH4OH 31Å 34Å 800 • Well-spaced p p porous p y polymer layer y 600 structure with ionic interior • Estimated pore size ~ 1 nm when dΔ n 400 molecular rods adapt random order • Anisotropic ‘in-plane’ pore dimensions 200 measured pKa • Upon electrolyte/water uptake: at monomer in-plane swelling 0 0 4 8 12 pH Philips Research Laboratories, D.J.Broer, Date(in numbers) Carmen Luengo
  33. 33. Opening of the network at high pH ClO4- N H2N O N CH3 CH3 reddish/colorless blue 2 0.04 t = 0 / pH>11 pH < 10.1-11.1 NH4OH solution 1.5 0.03 nce Absorban 1 0.02 t = 24 hrs 0.5 0.01 0 0 300 400 500 600 700 800 900 pH ~7 Wavelength (nm) Carmen Luengo Philips Research Laboratories, D.J.Broer, Date(in numbers)
  34. 34. Filling the ion channels with Ba2+ Philips Research Laboratories, D.J.Broer, Date(in numbers) Carmen Luengo
  35. 35. Insertion of dipyridines in monomeric state influences the pore sizes Forms a stable smectic complex: ~47 Å O O O O O (CH2)6 O O (CH2)6 O N HO OH N O ( SmX 110 I) O O O O O O O O O ~42 Å 43Å 43Å 43Å polymerization NH4OH at 110 oC cool to RT Estimated (XRD) pore sizes: 5 to 9 nm Carmen Luengo Philips Research Laboratories, D.J.Broer, Date(in numbers)
  36. 36. Applications being studied easy integration in nanolithography, e.g. μ-fluidic devices for nanoelectronics separation, e.g for water desalination clad inner surfaces, e.g. e g for catalysis templated polymerization, e.g. e g for anisotropic conduction ion conduction e.g. for batteries ion l ti i selection, e.g. for blue energy Philips Research Laboratories, D.J.Broer, Date(in numbers)
  37. 37. Summary • Engineering toolbox for top down/bottom up polymer network structuring • Top down: lithography/holography/printing mostly in the μm range; occasionally down to 50 nm • Bottom-up: control over molecular order structured down to nm level • Applications: Optics, mechanics, electronics, fluidics, separation, biosensors, …………………medical, clean technologies. Philips Research Laboratories, D.J.Broer, Date(in numbers)
  38. 38. With thanks to: The PICT group at TU/e The Biomolecular Engineering • Cees Bastiaansen - Associate Prof. group at Philips Research • Dick de Boer - Industrial Fellow (10%) • Johan Lub • Michael Debije - Postdoc • Emiel Peeters • Ko Hermans - PhD student • Roel Penterman • Carmen Luengo-Gonzalez - PhD student • Ralph Kurt • Xiaoran Li - PhD student (1/9-08) (1/9 08) • David Halter • Casper van Oosten - PhD student • Christiane de Witz • Katherine Pacheco Morillo - Postdoc • Titie Mol • Helena Plasschaert - PhD student • Hans Wilderbeek • An Prenen - PhD student • Thijs Bel Thij B l • Shufen Tjoi - PhD student • Jaap den Toonder • Joost Valeton - PhD student • Auke van Dijken • Shabnam Zakerhamidi - Staff • Harry Wondergem Just left • Chamindie Punyadeera • Chris van Heesch - finished PhD • Ron van Lieshout (now Philips Research Eindhoven) • Judith de Goede • Charlotte Kjellander - finished PhD • Murray Gillies (now TNO Holst Eindhoven) • Blanca Serrano-Ramon - finished PhD • Ken Harris - former postdoc (now NINT - Edmonton) Philips Research Laboratories, D.J.Broer, Date(in numbers)

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