Effect of terminal chain length on the helical twisting power in achiral bent-core molecules doped in a cholesteric liquid crystal

We prepared a homologous series of achiral bent-core (BC) liquid crystals with different terminal alkoxy chain lengths, <i>n</i> (BC-<i>n</i>), and evaluated the helical twisting power (HTP) of the BC-<i>n</i> doped in a cholesteric liquid crystal. The BC-<i>n</i> molecules with longer terminal chains showed larger HTPs. To interpret this striking phenomenon, a stochastic dynamics simulation was performed to determine the distribution of the chirality order parameters (<i>χ</i>) for BC molecules with <i>n</i> = 8-16. The distribution of <i>χ</i> for each simulated conformation varied with <i>n</i>, and the variation tendency was different for molecules with <i>n</i> < 12 and <i>n</i> > 12 despite the linear relationship between HTP and <i>n</i> in the experiment.