Thermosensitive micelles composed of poly(lactide)--poly(NIPAM--HEMA) graft copolymers

Quynh, T. M.*; Yoneyama, Masaru*; Maki, Yasuyuki*; Nagasawa, Naotsugu; Dobashi, Toshiaki*

Key Engineering Materials, 459, p.51 - 56, 2010/12

https://doi.org/10.4028/www.scientific.net/KEM.459.51

Different poly(-isopropylacrylamide--hydroxyethyl methacrylate) copolymers [P(NIPAM--HEMA)] were synthesized from -isopropylacrylamide (NIPA) and hydroxyethyl methacrylate (HEMA) monomers by both radical and radiation polymerizations for comparison. PLLA--P(NIPAM--HEMA) graft copolymers were synthesized from L-lactide and respective P(NIPAM--HEMA) copolymers by ring opening polymerization. Both NMR and FTIR analyses demonstrated the PLLA chains have been grafted on to the P(NIPAM--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.