Stability and Rupture of Liquid Crystal Bridges under Microgravity.

Liquid-crystal columns were prepared and observed under microgravity aboard suborbital TEXUS rocket flights. The microgravity phase of each flight lasted for approximately six minutes. We tested structures in different liquid-crystalline mesophases. In the isotropic and nematic phases, the Rayleigh-Plateau instability led to the collapse of the columns. However, in the smectic A and C mesophases, it was found that the columns survived the extension to slenderness ratios (length/diameter) of over 4.5 (and in one case, more than 6). The liquid-crystalline material in the millimeter-sized columns was macroscopically disordered. Thus, regular shell-like internal layer structures that stabilized the columns can be excluded. Instead, the reason for their persistence was the yield stress of the material, which is quite different for the different mesophases. In the columnar mesophase, the cylindrical bridge even survived the strong deceleration when the rocket re-entered the atmosphere. During the breakup of the filaments, the neck thinning dynamics were determined. [ABSTRACT FROM AUTHOR]