THE EFFECTS OF VARIATION OF A CORE RING-SYSTEM IN THE MESOGENIC SIDE-CHAIN OF LIQUID-CRYSTAL POLYSILOXANES

Fourteen novel side-chain polysiloxanes 2 and their alkene precursors 1 containing methylene-cyclohexane, cyclohexane, benzene, bicyclooctane, 3-oxobicyclooctane, bicyclohexane and biphenyl moieties in the mesogenic core, and with (CH2)n spacer lengths of n = 3, 6 and 11 are reported. The order of efficiency of these cyclic moieties in promoting liquid-crystal properties in the polymers is the same as that observed for the precursor alkenes, indicating that similar qualitative structural rules govern mesophase type and thermal stability in both monomeric and macromolecular systems. The apparent occurrence of smectic C properties for two of the polymers is particularly interesting.