Synthesis and characterisation of an unsymmetrical, ether-linked, fluorinated bimesogen exhibiting a new polymorphism containing the N-TB or 'twist-bend' phase

In this article we report on the liquid crystal phases and properties of the bimesogen 4-((11-((40-fluoro[1,10-biphenyl]-4-yl)oxy)undecyl)oxy)-2,3-difluoro-40-(4-propylcyclohexyl)-1,10-biphenyl. This material was shown to exhibit an Iso Liq-N-N-TB-SmA phase sequence, thereby clearly indicating that the N-TB phase possesses an ordering of the constituent molecules that is between that of a conventional nematic and the smectic A phase. This compound allows us to better understand the relationship between molecular structure and the NTB phase, and we conclude it is the gross topology that dictates the incidence of this fascinating phase and not molecular properties such as dipole moment and bend angle.