DMPC on mica
description
Transcript of DMPC on mica
DMPC on mica
Phospholipid monolayer
water subphase
Gleiche et al., Nature 2000, 403,173-175
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B. Pignataro, unpublished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) 524-529
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 airImmidiatly 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. 2001
Flow on an inclined planemm scale
P. Moraille et al., Langmuir 2002
10 µm x 10 µm , 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
subphasemonolayer
Substrate-surfactant forces density fluctuation
condensedexpanded
Instabilities are stronger at the three-phase contact line (stronger substrate-surfactant interaction)
Solid Substrate
H2O
Subs
trate
-sur
fact
ant
per
pend
icul
ar fo
rce
Distance from the three-phase contact line
Low speed
High speed
Original front
New front
Perpendicularpattern
Parallel pattern
Surf
acta
nt C
once
ntra
tion
(Pre
ssur
e)
Transfer Speed
0.5
0
Isotropic/Random
PeriodicParallel
PeriodicPerpendicularTr
ansit
ion r
egio
n
Compact
A. Raudino, B. Pignataro, Journal of Physical Chemistry B (Letter) 111 (2007) 9189