Synthesis and properties of α,ω-phenyl-capped bithiophene derivatives†
Abstract
Nine different α,ω-phenyl-endcapped bithiophenes were synthesised, and the effect of the different side chains on the liquid crystalline properties, alignment ability and charge carrier mobility have been studied. An increase in chain length leads to a decrease in the liquid crystalline–isotropic phase (clearing) transition temperature. Remarkably, introduction of an asymmetric carbon centre close to the π-conjugated segment resulted in the loss of the liquid crystalline phase. Alignment on rubbed polyimide was obtained for the liquid crystalline