250 likes | 425 Views
Capillary origami. José Bico PMMH-ESPCI, Paris. with Charlotte Py, Charles Baroud, Benoît Roman, Sébastien Neukirch, Arezki Boudaoud Loïc Moulin, Renaud Bastien, Lionel Doppler, Paul Reverdy, Aline Delbos, Ariane Calvar. PMMH-ESPCI, LadHyx, LPS-ENS, LMM-Paris6. Wet hairs.
E N D
Capillary origami José Bico PMMH-ESPCI, Paris with Charlotte Py, Charles Baroud, Benoît Roman, Sébastien Neukirch, Arezki Boudaoud Loïc Moulin, Renaud Bastien, Lionel Doppler, Paul Reverdy, Aline Delbos, Ariane Calvar PMMH-ESPCI, LadHyx, LPS-ENS, LMM-Paris6
Wet hairs nanotubes forest Chakrapani et al. 2004 2 mm 1 mm photoresist artificial gecko Tanaka et al. 1993 Geim et al. 2003
Macroscopic brushes 1mm with Loïc Moulin, Benoît Roman & Arezki Boudaoud Nature 2004
2-lamellae Lwet[mm] Ltotal Lstick d Lstick 2g hJurin = rgd Lwet Ltotal [mm] plastic transparency, d = 1mm, h = 100mm silicone oil
170 mm 100 mm Eh 3 50 mm Fracture Lstick/LEC 2 d g 3 Lstick Lstick Eh ~ Lstick 2 d Griffith, 1921 Lstick 1/4 3 Eh d ~ LECd Lstick ~ 1/2 1/2 1/2 g Elasto-capillary length LEC = g d/LEC
Multi-lamellae Lstick ~ NdLEC 2 2 4 3 d dN/2 Lstick[mm] Eh3N/2 Lstick N lamellae N lamellae
n(N) f(N/Nmax) Nmax = 2 Ntotal p actual brush ≠ 2 Self-similar distributions coalescence Nmax f(N/Nmax) 2 3 Nmax = 6 Nmax = 7 Nmax = 8 Nmax = 9 Nmax = 10 Nmax = 11 4 5 … fragmentation N/Nmax Arezki Boudaoud's talk
Fibres Elementary sticking or ? ?
d 1/2 1/2 3/8 Lstick ~ N d LEC d N/2 N/2 N/2 Lstick/d LEC 1/2 1/2 Eb3N/2 Lsec Eb 3 Fibre bundles LEC = g N with Renaud Bastien, Benoît Roman, Arezki Boudaoud & Charlotte Py Europhys. Lett. 2007
Eb 3 Piercing an interface F Euler buckling Hb F = 2pbg ? L EI p Lcrit = ~ g F 2 with Benoît Roman & Sébastien Neukirch JMPS 2007
Post-buckling Hb/Lcrit Hb L L/Lcrit continuous transition discontinuous transition Sébastien Neukirch's talk
Capillary origami 3d ? Flexible sheet L folds ? crumpling ? singularities ? with Lionel Doppler, Paul Reverdy, Benoît Roman, Charles Baroud & Charlotte Py Phys. Rev. Lett. 2007
Pyramids 1 mm
g /R d LEC = g g g Eh 3 S R Closes ? ... 2d simulation d/L L >3.5LEC S/L 2
g /R d LEC = g g g Eh 3 S R ... or reopens ? 2d simulation d/L L <3.5LEC S/L 2
Measuring LEC air liquid 0.89LEC angle = 0 elastica + B.C. curvaturture = √2/LEC
g Eh 3 LEC = Closing conditions (3d) Lcrit [mm] L Lcrit 7LEC 2D model: Lcrit 3,5LEC L LEC [mm]
Open questions role of edges, 3D model "ridge" ? sealing
EI R2 ~ R R2 DgR`/EI 3 Compressed ring surfactant g+ g- 1 cm A/A0 buckling: with Aline Delbos, Ariane Calvar, Benoît Roman, Denis Bartolo & Anne Juel
2D origami oil lense L > Lcrit L < Lcrit with Aline Delbos, Benoît Roman & Anne Juel
Eh 3 LEC = g Conclusion: elasto-capillarity bending + capillarity elastocapillary length h 3/2 dominant at small scales
Prospects: delamination ingredients : elasticity / adhesion biaxial compression 50 µm 5 mm 200 nm C on SiO2, Gille & Rau 1984 with Benoît Roman, Denis Bartolo & Pedro Reis
Acknowledgments Benoît Roman Arezki Boudaoud Société de Amis de l'ESPCI Loïc Moulin ACI jeunes chercheurs - CNRS Renaud Bastien Sébastien Neukirch Charlotte Py Charles Baroud Lionel Doppler Fabien Closa Aline Delbos Denis Bartolo Ariane Calvar Anne Juel Pedro Reis