Dielectric relaxation in liquid crystals exhibiting a reentrant phenomenon

Abstract
This paper presents the experimental results of the dielectric characterization of mesomorphic compounds exhibiting reentrant or double reentrant phases. The comparison of activation energies in the flip-flop rotation of molecules in the different phases leads us to conclude that : — the activation energy in the reentrant nematic phase is higher than that of the nematic phase, — the activation energy in the reentrant smectic A phase is similar to that of the reentrant nematic phase. To the best of our knowledge, this study presents the first complete dielectric characterization of the double reentrant phenomenon