The Previously Unclassified Smectic Phases of Bis-(4′-n-Heptyloxybenzylidene)-1, 4–Phenylenediamine (HEPTOBPD)

Re-examination of the bis-(4′-n-alkoxy-benzylidene)-1,4–phenylenediamines, particularly the heptyloxy homologue, by optical microscopy and differential scanning calorimetry has confirmed the existence of two hitherto unclassified smectic phases, which are now assigned the code letters J and K (SJ andSk