Effect of lateral fluoro substituents on the chiral liquid crystal materials derived from (S)‐1‐methyl‐2‐(2′‐methylsulphanylethoxy)ethanol

Abstract

Two series of chiral materials, the (R)‐1‐methyl‐2‐(2′‐methylsulphanylethoxy)ethyl 4‐(4′‐alkoxybiphenyl‐1‐carboxyloxy)‐2‐fluorobenzoates, 2F3H(m = 7–10), and the (R)‐1‐methyl‐2‐(2′‐methylsulphanylethoxy)ethyl 4‐(4′‐alkoxybiphenyl‐1‐carboxyloxy)‐3‐fluorobenzoates, 2H3F(m = 7–10), were synthesized for investigation. Polymorphism of the materials was detected primarily by polarizing microscopy and differential scanning calorimetry. The ferroelectric and antiferroelectric phases were further characterized by switching current behaviour, electro‐optical response and dielectric permittivity. The results show that the antiferroelectric phase occurred in two materials, 2F3H(m = 7) and 2H3F(m = 8). The spontaneous polarization and apparent tilt angle for the materials in the SmC* and/or phases were also measured. The effect of fluoro substituents on the physical properties of the materials is discussed.