Chiral Smectic Liquid Crystalline Polymers

The synthesis of side-chain liquid crystalline polysiloxanes, copolysiloxanes and of tetracyclosiloxanes containing chiral mesogenic side groups, i.e, trans- 2[p-(l-undecanyl-ll-oxy)phenyl]-5-[(p-2(S)- methyl-1-butoxy)pheny1]-1,3-dioxane, trans- 2-[p-(2(S)-methyl-1-butoxy)phenyl]-5-(11- undecalenyl)-1,3-dioxane and 2-[4-(2(S)- methyl-butoxy)-phenyl]-5-(w-alkl)-l,3,2- dioxaborlnane with alkyl being undecanyl, octyl, and hexyl is discussed. Differential scanning calorimetry and thermal optical polarization microscopy revealed chiral smectic mesomorphism for polymers containing eleven methylene units in the flexible spacer. The polymers containing undecanyl spacers present a chiral smectic C mesophase. The polysiloxanes with hexyl spacers exhibit a chiral nematic mesophase.