Antiphase behavior in the 4-n-alkoxybiphenylyl-4'-cyanobenzoates (nOBCB's).

The ways in which polar molecules can overlap to form bilayer structures have recently been the subject of many investigations. Consequently, a number of new smectic modifications have been defined which involve different forms of layering structure. For example, the smectic A phase has been divided into four basic groups by the different overlapping structures of the molecules; e.g. A1 (monolayer), A2 (bilayer), Ad (interdigitated bilayer), and A(-) (antiphase, in-plane modulated structuring). Similarly, the smectic C phase is being divided into subgroups along the same lines, e.g. C1 (monolayers), C2 (bilayer), and C (ribbon or antiphase, in-plane modulation).