Chirality in liquid crystals. The remarkable phenylpropiolates

The biphenylyl esters of the 4-n-alkoxyphenylpropiolic acids are a unique family of liquid-crystalline materials. In particular, when the biphenyl moiety of the compounds carries a chiral end-group, many optically active mesophases are created which exhibit unusual structures and physical properties. For instance, when the chiral group attached to the biphenyl moiety is 1-methylheptyl then Abrikosov, twist grain boundary smectic A* and antiferroelectric smectic C* phases are observed. The wide variety of chiral phases and electrochiral properties exhibited by this family of materials makes them ideal candidates for exploring chirality in the liquid-crystalline state. These investigations allow us to contrast and compare chirality dependent phenomena in liquid crystals, thereby producing a broader view of the concept of chirality in organized fluids than is traditionally presented.