Dielectric studies in the isotropic phase of six symmetrical azomethines with various number of benzene rings. Influence of the ionic conductivity

The dielectric properties of six symmetrical azomethines with various number of benzene rings were studied in the isotropic phase. The permittivity as well as the impedance spectra were analyzed because the only one relaxation process was visible in the permittivity spectra while two relaxation processes appear in the impedance presentation. It was found that the process at low frequency range, characterized by a very high dielectric increment and parameter α ~ 0.1, is attributed to the ionic motion, while the high frequency Debye-type process with the relatively small increment is connected with the dipolar rotation of the molecules (displacement current). The appearance of an abnormally high value of the static permittivity is discussed, which may be useful for biological and/or other molecular systems where the ionic conductivity is usually very high. •The impedance spectra of azomethines allow to distinguish two relaxation processes.•The very strong process at low frequency is attributed to the ionic motion.•The high frequency process is connected with the dipolar rotation of the molecules.•Activation energy of the dipolar rotation increases with increasing polarity of the terminal azomethine group.