Detailed optical studies of several banana-shaped compounds in liquid crystal B2 phase - art. no. 051713

Null-transmission ellipsometry has been performed on free-standing films of one compound in the liquid crystal B2 phase. We have studied films of thic kness from 1 to 121 layers. One of the compounds used has an unusually wide 59 K window for the B2 phase. The tilt angle was investigated as a functio n of temperature and found to be constant over this temperature range to wi thin our resolution of 1 degrees. The one-layer films studied exhibit the s ame structure as the thicker films, and have helped us to refine the optica l model for the B2 phase. For thin films we find that modeling a single sme ctic layer as two uniaxial layers is a better description of the data than a single biaxial layer, but that for thick films the model used does not ef fect the simulated result appreciably. Preliminary results also find that t he surface layers are less tilted than the interior layers, in contrast to rodlike liquid crystals, which show an enhanced surface tilt.