One-pot synthesis of pH- and thermo-sensitive chitosan-based nanoparticles by the polymerization of acrylic acid/chitosan with macro-RAFT agent

Thermo- and pH-sensitive chitosan-based nanoparticles were successfully prepared by one-pot polymerization of acrylic acid/chitosan with poly(N-isopropylacrylamide) (PNIPAM) macro-RAFT agent. The spherical and monodisperse nanoparticles were obtained with the diameters of about 100 nm at 25 degrees C (pH=6.5), and PNIPAM was anchored as the shell via the RAFT process. The disorder shell and the large aggregates were observed at 40 degrees C (pH=6.5); and the spherical nanoparticles broke up at 25 degrees C when pH was lowered to 3. This work may provide a facile "one-pot" method to prepare functionalized chitosan-based nanoparticles without N-phthaloylation of chitosan in the process.