Revisiting Smectic E Structure through Swollen Smectic E Phase in Binary System of 4-Nonyl-4′-isothiocyanatobiphenyl (9TCB) and n-Nonane

Thermodynamic and diffraction analyses were performed to establish the phase diagram for a binary system between 4-n-nonyl-4'-isothiocyanatobiphenyl (9TCB) and n-nonane. The swollen SmE structure is identified in the binary system. Upon swelling, a characteristic two-dimensional herringbone array is maintained whereas the layer spacing of SmE structure increases with the content of n-nonane. Considering the difficulties in explaining the experimental findings based on the traditional model of SmE structure, a new model, lamellar with two types of sublayers consisting of aromatic core and alkyl chain moieties, is proposed.