DMPC on mica

1. Solid supported super- structures (Out of equilibrium states) Phospholipid monolayer water subphase Transfer direction Gleiche et al., Nature2000,403,173-175 B. Pignataro et al., J. Phys. Chem. B 111 (2007) 9189 Chen et.al., JPCB, 110 (2006) 8041 DPPC on mica DPPC on mica DMPC on mica

2. Cell Receptors O. Purrucker, JACS 127 (2005) 1258 Other systems showing transfer speed dependent order in LB monolayers Au Nanoparticles Derivatized Flavonoids J. Huang, Nanoletters 6 (2006) 524-529 B. Pignataro, unpublished

3. Pattern selection by Speed Transfer modulation (temperature 10 °C, surface pressures 30 mN/m) 2 mm/min 7 mm/min 10 mm/min 20 mm/min 60 mm/min

4. Out of equilibrium system (Ageing of the ordered molecular surfaces) 15 days under air Immidiatly after transfer

5. Patterns in Nature and instabilities Different patterns can be found in Nature showing periodic structures along with anisotropy and fractal pathways. Also as to fluids, instability at the propagation front has been observed in gravity-driven falling films (viscous fingering) or in rising films under a temperature gradient. Moreover, by considering the preparation of functional materials, regular patterns are common features in directional solidification. In this case such a patterns originates from different drivers including heat flows, mass diffusion gradients, uniaxial stresses, or lattice mismatches, as in heteroepitaxy. These patterns are induced by instability effects and typically extend in the same direction of the moving front with periodicity ranging from millimeters (gravity forces) to microns (temperature gradients). Gravitational instabilities Viscous fingering Solidification instabilities

6. No gravity, intermolecular and surface forces !! LB mixed monolayer 10 µm x 10 µm , height scale3 nm P. Moraille et al., Langmuir 2002 Fingering instability Flow on an inclined plane mm scale M.Bestehorn et al, Phys. Rev. Lett. 2001

7. Substrate-surfactant forcesdensity fluctuation Height modulation of the incompressible water layer (surface tension < substrate-surfactant) condensed expanded monolayer subphase substrate Instabilities are stronger at the three-phase contact line (stronger substrate-surfactant interaction) Molecular film over a thin sub-phase layer on a solid substrate

8. H2O Solid Substrate

9. Original front New front Switching directionality mechanism Parallel pattern Low speed Substrate-surfactant perpendicular force Distance from the three-phase contact line Perpendicular pattern High speed

10. 0.5 0 Surfactant Concentration (Pressure) Compact Periodic Parallel Transition region Periodic Perpendicular Transfer Speed Isotropic/Random Qualitative phase diagram (non equilibrium states) of different patterns in solid supported LB monolayers A. Raudino, B. Pignataro, Journal of Physical Chemistry B (Letter) 111 (2007) 9189