Thermosensitive Micelles Composed of Poly(lactide)-g-Poly(NIPAM-co-HEMA) Graft Copolymers
Different poly(N-isopropylacrylamide-co-hydroxyethyl methacrylate) copolymers (P(NIPAM-co-HEMA)) were synthesized from N-isopropylacrylamide (NIPA) and hydroxyethyl methacrylate (HEMA) comonomers by both radical and radiation polymerizations for comparison. PLLA-g-P(NIPAM-co-HEMA) graft copolymers were synthesized from L-lactide and respective P(NIPAM-co-HEMA) copolymers by ring opening polymerization. Both NMR and FTIR analyses demonstrated the PLLA chains have been grafted on to the P(NIPAM-co-HEMA) backbone. These graft copolymers revealed the cloud point temperature higher than that of PNIPAM homopolymer as determined by optical transmittance. The graft copolymers self-assembled into micelles with regularly spherical structures as observed by atomic force microscopy (AFM). The properties of these graft copolymers are interesting for the drug delivery system.
Osamu Hanaizumi and Masafumi Unno
T. M. Quynh et al., "Thermosensitive Micelles Composed of Poly(lactide)-g-Poly(NIPAM-co-HEMA) Graft Copolymers", Key Engineering Materials, Vol. 459, pp. 51-56, 2011