Thermal convection experiment with very thin aqueous films.

We show first results on a thermal convection experiment with very
thin aqueous films. Film thinning is an important but very slow
process. for our experiment, we use an enhanced experimental setup and
extremely well--controlled chemistry :n-dodecyl-$?beta$-maltoside is
used as the surfactant stabilizing the sheet of water making it
possible to reach stable common and Newton black films. We demonstrate
how thinning can be enhanced by a temperature gradient which in turn
drives the film into a turbulent regime. Consequently, we analyze the
flow with respect to its mixing properties using statistical
tools. The mixing in each vortex is characterized by the average of
the stretching over the vortex area whereas the crossing of the
separatix describes the global mixing. Applying effective diffusion
and finite size analyhsis, we characterize the mixing efficiency in
terms of the probability distribution of increments in time and space.