Branched schiff base liquid crystalline oligomers: synthesis and properties.

Three series of new branched liquid crystal oligomers with 4-hydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid as the centre and cholesterol as the chiral group were designed and synthesised (Dn, Fn and Hn, n = 4,6,8). DSC and POM results showed that their liquid crystal phase behaviour was closely related to the number of mesogenic unit and the rigidity and flexibility of the structure. They were all cholesteric liquid crystals. In the same series, as the value of n increased, the mesophase ranges became narrower. When the value of n was the same in different series, as the degree of branching increased, the mesophase ranges became narrower. [ABSTRACT FROM AUTHOR]