Liquid crystalline derivatives of oligoethylene-amines and -amino ethers with amide, ester, urea or urethane functions

The mesomorphism of diethylenetriamine and triethylenetetramine derivatives, substituted with the 3,4-bis(decyloxy)benzoyl group (‘two chain’ substituent)via amide, ester, urea or urethane moieties, is described. Furthermore, different examples of related linear and cyclic oligoethyleneamino ethers are investigated and compared with the mesomorphism of the first group. Both lamellar smectic A and hexagonal columnar mesophases can be observed in linear compounds, depending on the length of the linear unit. A cyclic derivative displays a cubic phase. The conclusion is emphasized that the mesomorphism of these classes of compounds is caused by microphase separation.