DMPC on mica Phospholipid monolayer water subphase Gleiche et al., Nature 2000, 403, DPPC on mica Transfer direction Chen et.al., JPCB, 110 (2006) 8041 (Out of equilibrium states) B. Pignataro et al., J. Phys. Chem. B 111 (2007) 9189 DPPC on mica

Derivatized Flavonoids B. Pignataro, unpublished J. Huang, Nanoletters 6 (2006) Au Nanoparticles O. Purrucker, JACS 127 (2005) 1258 Cell Receptors

20 mm/min 60 mm/min 2 mm/min 7 mm/min 10 mm/min (temperature 10 °C, surface pressures 30 mN/m)

(Ageing of the ordered molecular surfaces) 15 days under air Immidiatly after transfer

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). Patterns in Nature and instabilities Viscous fingering Gravitational instabilities Solidification instabilities

M.Bestehorn et al, Phys. Rev. Lett Flow on an inclined plane mm scale P. Moraille et al., Langmuir µ m x 10 µ m, height scale 3 nm LB mixed monolayer No gravity, intermolecular and surface forces !!

Height modulation of the incompressible water layer (surface tension < substrate-surfactant) substrate subphase monolayer Substrate-surfactant forces density fluctuation condensed expanded Instabilities are stronger at the three-phase contact line (stronger substrate-surfactant interaction)

Solid Substrate H2OH2O

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

Surfactant Concentration (Pressure) Transfer Speed Isotropic/Random Periodic Parallel Periodic Perpendicular Transition region Compact A. Raudino, B. Pignataro, Journal of Physical Chemistry B (Letter) 111 (2007) 9189