Mesomorphic and luminescent properties of disubstituted polyacetylenes bearing biphenyl pendants

Abstract Liquid crystalline and light emitting properties of two new disubstituted polyacetylenes bearing biphenyl pendants (–{(R)CC[(CH2)4OCO-Biph-OC7H15]}n–, RCH3 (1), C6H5 (2), Biph=4,4′-biphenylyl) were investigated. Whereas 1 formed enantiotropic nematic phase, 2 was non-mesomorphic. Upon photoexcitation, the THF solutions of 1 and 2 emitted strong UV and blue light of 369 and 460 nm, respectively, whose quantum efficiencies were higher than that of poly(1-phenyl-1-octyne), a highly luminescent disubstituted polyacetylene.