Ion polarisation-assisted hydrogen-bonded ferroelectrics in liquid crystalline domains

An alkylamide-substituted (−NHCOC(10)H(21)) hydrogen-bonded dibenzo[18]crown-6 derivative (1) was prepared to stabilise the ionic channel structure in a discotic hexagonal columnar (Col(h)) liquid crystal. The introduction of simple M(+)X(−) salts such as Na(+)PF(6)(−) and K(+)I(−) into the ionic channel of 1 enhanced the ionic conductivity of the Col(h) phase of the M(+)·(1)·X(−) salts, with the highest ionic conductivity reaching ∼10(−6) S cm(−1) for K(+)·(1)·I(−) and Na(+)·(1)·PF(6)(−) at 460 K, which was approximately 5 orders of magnitude higher than that of 1. The introduction of non-ferroelectric 1 into the ferroelectric N,N′,N′′-tri(tetradecyl)-1,3,5-benzenetricarboxamide (3BC) elicited a ferroelectric response from the mixed Col(h) phase of (3BC)(x)(1)(1−x) with x = 0.9 and 0.8. The further doping of M(+)X(−) into the ferroelectric Col(h) phase of (3BC)(0.9)(1)(0.1) enhanced the ferroelectric polarisation assisted by ion displacement in the half-filled ionic channel for the vacant dibenzo[18]crown-6 of (3BC)(0.9)[(M(+))(0.5)·(1)·(X(−))(0.5)](0.1).