Novel branched liquid crystal oligomers containing azo and Schiff base groups

Abstract

Three novel azo-Schiff base mesogens with different alkyl chain lengths and three series of novel branched liquid crystal oligomers with 4-hydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid as the center and cholesterol as the chiral group were designed and synthesized. The test results showed that their liquid crystal phase behavior was closely related to the number of mesogenic units and the rigidity and flexibility of the structure. In the same series, as the value of n increased, the mesophase ranges were widened. When the value of n was the same in different series, as the degree of branching increased, the mesophase ranges were widened.