Synthesis and characterization of poly(propylene imine)-based liquid crystalline dendrimers

Poly(propylene imine)-based liquid crystalline dendrimers (PPILCDs) with a relatively flexible dendritic scaffold were successfully synthesized by rea ction of poly(propylene imine) dendrimers with 4'-cyanobiphenyl hydrogen gl utarate in the presence of condensing agent, diphenyl(2,3-dihydro-2-thioxo- 3-benzoxazolyl)phosphonate. The structures of PPILCDs were characterized by IR, H-1 NMR and MALDI-TOF mass spectroscopies and elemental analysis. Thes e LCDs did not show a thermotropic liquid crystalline nature, but exhibited the liquid crystalline textures in the samples sheared at 70 degrees C. Fu rthermore, they showed a lyotropic liquid crystalline property in the 80 wt % DMF solutions.