NAPHTHALENE SYSTEM AS THE ORIGIN OF UNCONVENTIONALLY SHAPED FERROELECTRIC LIQUID-CRYSTALS

On the basis of the possibilities of disubstitutions that the naphthalene ring offers, the liquid-crystal and ferroelectric properties of new chiral [1,5]-, [1,6]-, [2,3]-, [2,5]-, [2,6]-, and [2,7]naphthyl benzoates are reported. These new structures have molecular shapes of different linearity which significantly influences both the liquid-crystal behavior (only the [2,6] derivatives form a liquid crystal) and the ferroelectric response of the products that were evaluated in binary mixtures. While the stepped [1,5]- and [2,6]naphthalene structures can be considered useful alternatives to the linear biphenyl ones for ferroelectric blends, the behavior of the angled compounds ([1,6], [2,3], [2,5], and [2,7]) strongly depends on the chiral tail position: on the benzoate ring or on the naphthyl one. For the latter, as well as a worse dipolar coupling, the bending structure obliges the chiral tail to adopt conformations that lead to a significant lowering of the macroscopic polarization of the material.