  Freely suspended films of smectic liquid crystals are unique examples of
quasi two-dimensional fluids. Mechanically stable and with quantized thickness
of the order of only a few molecular layers, smectic films are ideal systems
for studying fundamental fluid physics, such as collective molecular ordering,
defect and fluctuation phenomena, hydrodynamics, and nonequilibrium behavior in
two dimensions (2D), including serving as models of complex biological
membranes. Smectic films can be drawn across openings in planar supports
resulting in thin, meniscus-bounded membranes, and can also be prepared as
bubbles, either supported on an inflation tube or floating freely. The
quantized layering renders smectic films uniquely useful in 2D fluid physics.
The OASIS team has pursued a variety of ground-based and microgravity
applications of thin liquid crystal films to fluid structure and hydrodynamic
problems in 2D and quasi-2D systems. Parabolic flights and sounding rocket
experiments were carried out in order to explore the shape evolution of free
floating smectic bubbles, and to probe Marangoni effects in flat films. The
dynamics of emulsions of smectic islands (thicker regions on thin background
films) and of microdroplet inclusions in spherical films, as well as
thermocapillary effects, were studied over extended periods within the OASIS
(Observation and Analysis of Smectic Islands in Space) project on the
International Space Station. We summarize the technical details of the OASIS
hardware and give preliminary examples of key observations.
