Ferroelectric response in an achiral non-symmetric bent liquid crystal:C12C10

Abstract

An achiral Non-Symmetric Bent Liquid Crystal (BLC) with a Oxadiazole based hetero cyclic central moiety, abbreviated as C12C10 viz., dodecyl[4-{5-(4′-decyloxy)biphenyl-4-yl}-1,2,4-oxadiazol-3-yl]benzoate, exhibiting FerroElectric (FE) response is reported. Product is confirmed by 1H NMR, 13C NMR and elemental analysis. Characterization of BLC phases is carried out by Polarized Optical Microscopy (POM), Differential Scanning Calorimetry (DSC), Spontaneous Polarization (PS) and Low Frequency (10Hz–10MHz) Dielectric Relaxation studies. C12C10 exhibits enantiotropic LC SmA, FE B2, SmG, SmE phase variance. I–SmA, B2–SmG and SmG–SmE transitions are of first order nature. FE B2 phases exhibits a moderate PS of ~80nCcm−2. B2 phase exhibits Curie–Weiss behavior to confirm FE nature. Off-centered low frequency (KHz) dispersion infers a scissor mode and a high frequency (MHz) mode to reflect the distinct time-scale response. Dielectric Dispersion is relatively susceptible in lower frequency KHz region. Arrhenius shift in Relaxation Frequency (fR) infers higher activation energy (Ea) in non-FE phases for HF mode and lower value for KHz mode. Trends of fR, dielectric strength Δε, α-parameter and Ea are discussed in view of the data reported in other LC compounds.