Synthesis of liquid crystalline polysiloxanes containing naphthalene-based mesogens and chiral side chains

Abstract

The synthesis and characterization of side-chain liquid crystalline polysiloxanes containing (2S)-2-chloro-4-methylpentyl 4-[(6-alkanyloxynaphthyl-2-yl)carbonyloxy]benzoate and (2S,3S)-2-chloro-3-methylpentyl 4-[(6-alkanploxynaphthyl-2yl)carbonyloxy]benzoate side groups are presented. All of the obtained polymers reveal respectively an enantiotropic smectic A phase. The phase transition temperatures of the obtained polymers depend on the spacer length. As the spacer length increases the glass transition temperature decreases while the isotropization temperature increases. The thermal stability of the obtained polymers increases as the spacer length increases. All of the obtained polymers present no chiral smectic C phase. The result seems to demonstrate that incorporation of a naphthalene ring in the mesogenic core decreases the tendency to form a chiral smectic C phase.