Effect of fluorine atoms in flexible chains on the phase transitions and photophysical behavior of D–π–A-type 4-alkoxy-4′-cyanodiphenylacetylene

Abstract

D–π–A-type 4-alkoxy-4′-cyanodiphenylacetylenes bearing a decyloxy chain show a nematic liquid crystalline (LC) phase, whereas the incorporation of a semifluoroalkyl fragment results in a switch to the smectic A phase. The D–π–A-type π-conjugated mesogen exhibits photoluminescence, not only in solution and in the crystalline phase, but also in the molecular aggregated structure of the LC phase.