Synthesis of Poly(N-isopropylacrylamide)-Poly(ethylene glycol) Miktoarm Star Copolymers via RAFT Polymerization and Aldehyde-Aminooxy Click Reaction and Their Thermoinduced Micellization

A facile synthetic pathway to poly(N-isopropylacrylamide) (PNIPAM) poly(ethylene glycoi) (PEG) miktoarm star copolymers with multiple arms has been developed by combining reversible addition fragmentation chain transfer (RAFT) polymerization and aldehyde-aminooxy click coupling reaction Sift! PNIPAM with aldehyde functionalized core was initially prepared by the RAFT arm-first technique via class-linking of the preformed linear macro-RAFT agents using a newly designed aldehyde-containing divinyl compound 6,6'-(ethane-1.2-diylbis(oxy))bis(3-vinylbenzaldehyde) (EVBA) It was then used is a multifunctional coupling agent for the subsequent formation of the second-generation PEG arms via the click coupling reaction between its aldehyde groups and aminooxy-terminated PEGs The ther mom responsive micellization behavior of PNIPA M PEG miktoarm star copolymer with different PEG ann numbers in water was also investigated Opportunities ale open for thermoinduced intermolecular or intramolecular micellization of PNIPAM PEG miktoarm star copolymers via controlling the content ratio of PNPAM and PEG, forming mull molecular micelles and unimolecular micelles, rspectively