The heliconical nematic twist-bend phase from “classic” bent-core benzylideneanilines with oligomethylene cores

ABSTRACT

We report the synthesis and properties of several new heliconical twist-bend nematic (N_TB) bimesogens possessing “classic” bent-core benzylideneaniline wings combined with oligomethylene spacers of odd parity. While short alkoxy tails combined with a resorcinol diester core in the classic system appear to give SmA phases (not B2 phases), in the present system, methoxy or ethoxy tails exhibit the N_TB phase as evidenced by textural analysis. Several of these compounds also exhibit microscopic helical defect structures in the N_TB phase, which have been reported in other lamellar and pseudo-lamellar liquid crystal phases, but not in the N_TB phase.

KEYWORDS:

• Nematic twist-bend phase
• double-helical defects
• benzylideneaniline bimesogens