抄録
Helical structures formed by smectic-A lilaments in an isotropic phase have been observed in the binary mixture of octyloxycyanobiphenyl and dodeeyl alcohol using a polarizing microscope. In 1984, helical ribbons of chiral lipid bilayers have been reported while smectic-A helical filaments observed here are tubular filaments. The existence of Smectic-A helical lilaments have also been theoretically investigated. The shape equation for smectic-A filaments has been derived by a variation of the sum of Gibbs free energy, curvature elastic energy and surface energy of the filaments. It is found that the smectic-A helical filaments are a solution to the shape equation.