STRIPE DOMAIN PHASE OF A THIN NEMATIC FILM AND THE K13 DIVERGENCE TERM

To verify the status of the divergence K13 term in the elastic theory of liquid crystals we study submicron films placed onto an isotropic f luid substrate in the Langmuir trough (Langmuir liquid crystal, LLC). The upper and lower surfaces favor normal and tangential molecular ori entation, respectively. The periodic domain phase is observed in a nem atic LLC. The dependence of the periodicity L of the domains vs film t hickness h can be explained only if the elastic energy is accompanied by divergence terms with nonzero constants K13 and K24. It is found th at for 5CB K13 almost-equal-to -0.2K11.