Authors: L.A. Picos-Corrales, A. Licea-Claveríe, K.-F. Arndt
Affilation: Instituto Tecnologico de Tijuana, Mexico
Pages: 644 - 647
Keywords: nanogels, stimuly responsive polymers, electron beam irradiation
Nanogels have attracted growing interest owing to their potential for applications in drug delivery systems. In this work, responsive nanogels based on amphiphilic block copolymers crosslinked in the micellar state were prepared by electron beam irradiation. The following amphiphilic block copolymers were used in this study: PNIPAAm-b-PSt, PNIPAAm-b-PHA, poly(NIPAAm-co-acid comonomer)-b-PSt and poly(NIPAAm-co-acid comonomer)-b-PHA; where HA is n-hexylacrylate, NIPAAm is N-isopropylacrylamide and St is styrene. The influence of the irradiation dose on the outcome of the nanogel formation, was tested. The materials were thoroughly characterized by dynamic and static light scattering before and after the irradiation. The T/pH-sensitive behavior of nanogels was also studied. The radius of gyration and hydrodynamic radius decreases slightly with increasing irradiation dose due to the increased crosslinking density. The second virial coefficient decreases with increasing irradiation dose indicating that the interactions within the polymer segments are getting more preferred to the interaction between polymer segments and solvent molecules. Nanogels were also prepared starting from a mixture of block copolymers with different LCST. The ρ-ratio of the nanogels is consistent with the experimental values obtained for core-shell morphology of flexible polymers. The nanogels from blended block copolymers showed a T/pH-sensitive behavior that mimic an ideal drug carrier.