Dynamics of freely floating smectic bubbles

We introduce smectic freely floating microbubbles and report their unusual dynamic properties. In equilibrium, they form minimal surfaces like soap films, but shape transformations of closed smectic membranes not in contact with menisci involve complex layer rearrangements. Very small distortions of the spherical equilibrium shape can relax by damped oscillations, driven by surface tension. Larger film area changes require the creation and motion of islands and layer dislocations. Then, film area changes are slow compared to natural oscillation frequencies. Quasi-stationary intermediate shapes evolve on the time scale of dislocation dynamics. These shape transformations are reminiscent of vesicles, in which the surface tension is effectively zero. We prepare smectic shells from collapsing catenoids and analyze their behavior with optical high-speed imaging.