Thermotropic Liquid Crystalline alfa-(bis(2-hydroxyethyl) amino)-w-(4’-nitroazobenzene-4-oxy) Alkane Hydrochlorides

We investigated the liquid crystalline hydrochlorides alfa-(bis(2-hydroxyethyl)amino)-W-(4’-nitroazobenzene-4-oxy)alkanes with different spacer lengths (2, 4, 6, 8, and 10 methylene units). LC properties were determined by thermal analysis (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD). DSC thermograms exhibit only melting peak with no LC transitions. LC phase was observed with POM and confirmed by XRD. All hydrochlorides form a smectic phase that is stable up to 220 °C where isotropization proceeds simultaneously with degradation.