Investigation of antiferroelectric liquid crystalline free-standing films by transmission ellipsometry

Thin free-standing films (FSFs) of an antiferroelectric liquid crystal (AFLC) were investigated by transmission ellipsometry. The phase difference between p-polarized and s-polarized light was measured as a function of the temperature and the incidence angle of the light beam. It was found that the structure of an FSF with two layers is anticlinic (SmCA*) throughout the temperature range investigated whereas the bulk sample shows several phases, from SmCA* to SmA phases. The four layer FSF showed only one phase transition (from SmCA* to SmA) in this temperature range. Even for such a thin film as one with five layers, a subphase or subphases between SmCA* and SmA were found.