Janus Dendrimer from Poly(Aryl Ether) Linked PAMAM for Supergelation and Guest Release

The present work reports an easy-to-make procedure of Janus dendrimers containing two most widely used dendrons [poly(aryl ether) and poly(amido amine) {PAMAM}], and utilize them, for the first time, to form a hydrogel with supergelation ability. The first generation (G1G1) Janus dendrimer forms hydrogel with a critical gelation concentration (CGC) of 6.5 mg/mL, whereas the CGC for G1G1.5 dendrimer went as low as 0.90 mg/mL in DMSO-H2O mixture. Judicious choice of solvent medium (ethanol-water) led to the formation of flexible morphology (long fibres to vesicles) by the Janus dendrimers, suggesting the possibility of tuning the mechanism of self-assembly in the system. The dye (rhodamine B) loading efficiency in the gel was successfully carried out using different generations {G1G1 and G1G1.5} of the Janus dendrimer. Generation G1G1 hydrogel (1 wt%) showed maximum dye loading efficiency of 4 mg/mL. Rhodamine B release profiles from the Janus dendrimers were determined and the results indicate that slow release kinetics was observed in the case of G1G1, where the self-assembly is robust.