New fluorine-containing ferroelectric liquid crystal compounds showing tristable switching

To understand the real cause of stabilization of the third state and to assure the possible application of the tristable switching, we have studied the effect of chiral centers on the appearance of the third state, synthesizing (R)-(+)- and (S)-(–)-4-(1-trifluoromethylalkoxy(n)carbonyl) phenyl 4′-alkoxy(m)biphenyl-4-carboxylate where m = 8, 9, 10, or 12 and n = 6 or 8; note that the chiral centre has a trifluoromethyl group. By observing light transmittance and switching current responses to a triangular voltage wave and by taking stroboscopic micrographs, we have confirmed that all the materials synthesized show the tristable switching in wide temperature ranges; in particular, the materials with m = 10 or 12 and n = 6 have the stabilized third state even at temperatures below 30°C.