Revisiting a family of liquid crystalline methacrylic phenyl benzoate monomers

Abstract

The synthesis and phase characterization of a homologous series of 4′-alkyloxyphenyl 4-(6-(methacryloyloxy)hexyloxy))benzoate monomers have been carried out. The characterization comprises polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and temperature dependant small and wide-angle x-ray scattering (SAXS –WAXS). The X-ray data and POM images reveal both the nematic and monolayered orthogonal smectic A phase in M6En series. The monomers with a terminal chain length from five to twelve carbon atoms exhibit a wide temperature range of a stable smectic A phase with a narrow intervening nematic phase at higher temperatures. On cooling down from the isotropic phase the temperature range of the nematic and smectic A phase considerably increases. The specific features of the phase diagram and mesogenic properties of M6En series are discussed in terms of the peculiar molecular structure of these monomers.