Properties of side chain liquid crystal polyesters containing chiral groups in the main chain

The synthesis and investigation are reported for the phase behavior of a set of three liquid-crystalline side chain polyesters (SCLCPs), consisting of aromatic diacids and diols bearing cyano biphenyl moieties in the side chain. The materials contain a chiral center in the main chain and show a cholesteric phase indicative of a helical order with a preferred twist. In addition, they exhibit [T.sub.g]'s below room temperature and smectic bilayer phases. Depending on the substitution pattern of the aromatic core, [S.sub.[C.sup.*]], or [S.sub.[A.sup.*]] phases are observed. These polymers were synthesized in a four-step synthesis, starting from available materials. The dielectric relaxation behavior and the pyroelectric responses of the three SCLCPs tend to conform to their respective structure.
INTRODUCTION For a side chain liquid crystal polymer (SCLCPs) to have potential use in electro-optical devices, low viscosities at room-temperature are necessary. To achieve this, polymers of a relatively low [...]