Synthesis and Characterization of Poly(methylsiloxane)s Containing 5-[S(-)-2-Methyl-1-butyl]-2-[4-(11-undecan-1-yloxy)phenyl]-1, 3, 2-dioxaborinane and 2-{4-[S(-)-2-Methyl-1- butoxy]phenyl}-5-(11-undecan-1-yl)-1, 3, 2-dioxaborinane Constitutional Isomeric Side Groups

Abstract

Abstract The synthesis and characterization of a poly(methylsiloxane) (16) and a poly(methyl-co-dimethylsiloxane) (17) containing 5-[S(-)-2-methyl-1-butyl]-2-[4-(11-undecan-1-yloxy)phenyl]-1, 3, 2-dioxaborinane mesogenic units are presented. Their mesomorphic behavior is compared to that of a poly(methylsiloxane) (18) and a poly(methy1-co-dimethylsiloxane) (19) containing the 2-(4-[S(-)-2-methyl-1-butoxy]-phenyl}-5-(11-undecan-1-yl)-1, 3, 2-dioxaborinane constitutional isomeric side groups. 16 exhibits a monotropic sA mesophase which undergoes the isotropicanisotropic transition at 27°C while 18 an enantiotropic sA mesophase which undergoes isotropization at 99°C. Both 16 and 18 display side chain crystallization. An explanation for the difference between the behavior of 16, 17 and of 18, 19 is provided.