Use of dielectric spectroscopy for evidencing subphases in an antiferroelectric liquid crystal

摘要

The analysis of an orthoconic antiferroelectric liquid-crystalline mixture, using dielectric spectroscopy, has revealed a plurality of ferroelectric smectic C* subphases. A great variety of relaxation responses that could indicate the presence of different SmC* subphases has been observed with the differential scanning calorimetry (DSC) technique in partial agreement with other techniques as DSC and optical microscopy. They represent smectic intermediate variants between the ferroelectric phase and the antiferroelectric one, whose study is still open and is collecting a lot of interest in academic field. The results obtained by dielectric spectroscopy were compared with other techniques as differential scanning calorimetry and polarized optical microscopy. The results demonstrate the possibility of using dielectric spectroscopy to highlight subphases that cannot be observed with conventional experimental techniques.