Synthesis, surface and aggregation properties of a series of amphiphilic dendritic copolymers

With 3.0 G polyamidoamine (PAMAM) as initiator and poly (propylene oxide) (PPO)–poly (ethylene oxide) (PEO) blocks as branches, a new class of amphiphilic copolymers were synthesized. The critical micelle concentration (CMC) and γ_CMC (surface tension at CMC) values were determined by surface tension measurement, and the result showed that they both decrease with the increase of amphiphilic branch length. The turbidity properties were investigated and it was found that the cloud point (CP) temperature decreases as the PEO block length increases. Freeze-fracture transmission electron microscopy (FF-TEM) results exhibited spherical shape of aggregates with the most probable distribution size of around 100 nm, which agrees with the results of the dynamic light scattering (DLS). Moreover, the relationship between PPO block length and the activity and CP properties was discussed.