SYNTHESIS AND CHARACTERIZATION OF CHIRAL SMECTIC SIDE-CHAIN LIQUID-CRYSTALLINE POLYSILOXANES CONTAINING 2,5-DISUBSTITUTED-1,3-DIOXANE BASED MESOGENIC SIDE-GROUPS

Abstract

The synthesis of three liquid crystalline polysiloxanes containing 4-[(S)-2-methyl-1-butoxycarbonyl]phenyl 4-(trans-5-alkanyl-1,3-dioxan-2-yl]benzoates side groups is presented. The phase behavior of both monomeric and polymeric liquid crystals was characterized by optical polarizing microscopy, differential scanning calorimetry and X-ray diffraction measurements. The monomer which contains eleven methylene units in the spacers is the only one to exhibit the enantiotropic smectic A and chiral smectic C phases. The polymer containing six methylene units in the spacers presents an enantiotropic smectic A phase while the polymer containing eleven methylene units in the spacers shows an enantiotropic smectic A and a monotropic smectic B phase.