Synthesis and mesomorphic properties of achiral swallow-tailed liquid crystals derived from diethylaminoalkanols

A homologous series of achiral swallow-tailed compounds derived from diethylaminoalkanols was designed and synthesized for the investigation of mesomorphism. Spectral analyses were in accord with the expected structures. Polarizing microscopy showed that all the compounds exhibit SmA and SmC_alt phases. The existence of the SmC_alt phase was confirmed by a significant first-order SmA-SmC_alt phase transition in the DSC traces, and by the appearance of a schlieren texture with a large number of four-brush and a small number of two-brush singularities under microscopy.