Deutsche Tagung f ¨ur Forschung mit ... - SNI-Portal

Weiche Materie Poster: Do., 13:00–15:30 D-P342
In-situ investigation of non-equilibrium flow on gradient surfaces.
J.-F. Moulin 1 , P. Müller-Buschbaum 1 , P. Uhlmann 2 , M. Stamm 2
1 Technische Universität München, Physik Department E13, James-Franck-Str. 1,
85747 Garching (Germany) – 2 Leibniz Institut für Polymerforschung Dresden e.V.
(IPF), Hohe Str. 6, D- 01069 Dresden (Germany)
To date, the development of microfluidic devices is limited by the lack of fundamental
understanding of the physical phenomenon that take place at the interface between
a complex fluid (e.g. a multicomponent polymer blend or solution) and a surface.
Overcoming the phenomenological descriptions of the progression of fluid fronts, phase
separation and ordering processes at surfaces would bring new opportunities to taylor
the properties of a substrate in order to control the behaviour of complex fluids and
therefore perform specific tasks (spatial control of chemical reactions, patterning).
Our approach to these problems is a multidisciplinary one, involving groups with
expertise in the field of sample preparation (generating a surface free energy gradient
at the ad hoc lengthscale), characterisation (via real space microscopic techniques and
scattering of X-rays and/or neutrons for the reciprocal space) and theoretical modelling.
We have concentrated our attention on motion of liquids confined in geometries with
gradually changing conditions, and more specifically on systems where the wall properties
display a linear gradient. The properties studied can be either physical (such as
the surface roughness) or chemical such as the composition.
We will here report on the reciprocal space investigation of the fluid´s internal structure
variations induced by the presence of the interface.