Coexistence of nematic and chiral nematic phases of an achiral liquid crystal trimer possessing an octafluorobiphenyl unit

ABSTRACT

We prepared some achiral flexible liquid crystal oligomers possessing an octafluorobiphenyl unit and investigated their phase transition properties using polarising optical microscopy and differential scanning calorimetry. All the compounds showed nematic phases. The trimer with even-numbered spacers was found to exhibit coexistence of the nematic regions and the chiral nematic regions with opposite twist senses of a sample contained in a homogeneous aligned cell during a cooling process, whilst that with odd-numbered spacers did not. We discuss how the even-numbered trimer produces the helical state.

GRAPHICAL ABSTRACT

KEYWORDS:

• Phase separation
• liquid crystal
• trimer
• nematic
• chirality
• symmetry breaking

Disclosure statement

No potential conflict of interest was reported by the authors.