Macromolecules, Vol.36, No.3, 565-572, 2003
Liquid crystalline oligo(p-phenylene vinylene)-terminated poly(propylene imine) dendrimers. Synthesis and characterization
Different generations of poly(propylene imine) dendrimers modified peripherically with urea oligo(p-phenylene vinylene)s (OPV) having a 3,4,5-tri(dodecyloxy)phenyl mesogenic unit (OPV-dendrimers) were successfully synthesized and fully characterized. Although intramolecular H-bonding exist between the urea linkages of the end groups, only weak interactions between the pi-conjugated segments were observed in solution. The hydrogen-bonding interactions increased for higher generation dendrimers due to the closer proximity of the end groups, indicative of a more dense-shell packing. All generations of OPV-dendrimers showed liquid crystalline behavior in which the OPV-dendrimers have a homeotropic orientation. The temperature range of the liquid crystalline phase increased with higher generation.