Liquid-crystalline comb copolymers with lipoamino acid side chains Synthesis and structure study

In order to obtain liquid-crystalline polymers without using classical mesogenic groups, comb copolymers consisting of a polyacrylamide main chain and lipoamino acid side chains have been synthesized. These copolymers were obtained by the polymerization of lipoamino acid macromonomers. These macromonomers were obtained from, α,ω-aliphatic amino acids by linking a polymerizable group at the amino end and an α-amino acid at the carboxyl end. The macromonomers were then transformed into comb copolymers by free-radical polymerization. These comb copolymers exhibit mesophases both in aqueous solution and in the anhydrous state. The range of stability and the structures of the mesophases were determined by X-ray diffraction. Two types of structures were found, corresponding to the lyotropic lamellar and hexagonal mesophases. The influences of the nature of the amino acid and the water concentration on the domain of stability and the geometrical parameters of the mesomorphic structures were investigated.