Bisensitive core-shell nanohydrogels by e-Beam irradiation of micelles

Sensitive nanohydrogels based on micellar aggregates from amphiphilic block copolymers were synthesized by means of electron beam irradiation. The crosslinked shell consists of temperature sensitive [N-isopropylacrylamide (NIPAAm)] and pH sensitive [5-methacryloyloxy pentatonic acid (5MPA) or 4-methacryloyloxy benzoic acid (4MBA)] units, while the core is a hydrophobic network that may work as a reservoir for drugs. The effect of the irradiation dose and the polymer concentration were tested. Dynamic and static light scattering were combined to investigate the morphology of aggregates prior and after irradiation to obtain nanohydrogels. Hydrodynamic radius of nanogels is in the range from 18 to 44 nm. ρ-Parameter suggests that crosslinked aggregates of flexible chains were obtained. Mixtures of block copolymers with different phase transition behavior in each aggregate lead to the preparation of nanohydrogels with tailored phase transition behavior.