New Architectures for Side Chain Liquid Crystalline Polymers with Chiral Smectic C Mesophases

Abstract

Abstract All attempts at synthesizing side chain liquid crystalline polymers (SCLCPs) with chiral smectic C (sc*) mesophases simply functionalize one terminal group of the mesogen with a chiral substituent and attach the other terminus to the polymer backbone through a spacer. If a sc* mesophase is observed, it is usually in the less desirable sc*-sA phase sequence. We propose that SCLCPs with laterally attached (vs terminally attached) mesogens offer an ideal architecture for obtaining sc* meso- phases. This is because extended mesogens symmetrically disubstituted with long n-alkoxy groups can be attached to the polymer backbone through a chiral spacer. Thus, mesogens which typically form the desirable sc*-n phase sequence can be used, and the chiral group can be introduced at the center of the mesogen which should result in high values of spontaneous polarization. We are not only using mesogens which exhibit sc*-n phase sequences, but are also attempting to induce smectic layering into laterally attached systems which typically form nematic mesophases by electron-donor-acceptor interactions and immiscible hydrocarbon/fluorocarbon components. Smectic layering was successfully induced in 2,5-bis[(4'-n-alkoxybenzoyl)oxy]toluenes when the n-alkoxy substituents were terminated with perfluorinated segments.