Ultrashort helix pitch antiferroelectric liquid crystals based on chiral esters of terphenyldicarboxylic acid

Antiferroelectric liquid crystals (AFLCs) with a nanoscale helix pitch (<100 nm) were revealed in a composition containing achiral smectic-C biphenylpyrimidines and two non-mesogenic chiral dopants: p-terphenyldicarboxylates of chiral (2S)-1,1,1-trifluorooctane-2-ol and (S,S)-1,1,1-trifluorooctan-2-yl 2-hydroxypropanoate. The prepared multicomponent AFLCs exhibit two electro-optical effects, which are interrelated with the chemical structures of the mixture's components. The first effect is hysteresis free under special voltage waveform U-shaped switching, which exhibits an electro-optical response similar to that of nematic liquid crystals (NLCs) but around 1-2 orders of magnitude faster. Secondly, the deformed helix antiferroelectric liquid crystal (DHAFLC) effect has been investigated. The observed temperature independence of the electro-optical parameters, in a certain temperature range, combined with a fast U-shape response or with DHAFLC, adds a great value for applications.