Controlled synthesis of stimuli-responsive polymers derived from amino acids

POLY 691

Hideharu Mori, h.mori@yz.yamagata-u.ac.jp, Motonobu Matsuyama, Ikumi Kato, Hideyuki Iwaya, and Takeshi Endo, tendo@yz.yamagata-u.ac.jp. Department of Polymer Science and Engineering, Faculty of Engineering, Yamagata University, 4-3-16, Jonan, Yonezawa, 992-8510, Japan
We report controlled synthesis of stimuli-responsive polymers having amino acid moieties by reversible addition-fragmentation chain transfer (RAFT) polymerization. Four acrylamides, N-acryloyl-L-phenylalanine methyl ester (A-Phe-OMe), N-acryloyl-L-proline methyl ester (A-Pro-OMe), N-acryloyl-L-phenylalanine (A-Phe-OH), and N-acryloyl-L-proline (A-Pro-OH), were selected as amino acid-containing monomers. The RAFT polymerization of these monomers using suitable chain transfer agents allowed the synthesis of well-defined amino acid-based polymers with characteristic stimuli-responsive properties. The poly(A-Phe-OH) and poly(A-Pro-OH) are weak polyelectrolytes, in which the degree of ionization of carboxylic acids can be easily controlled by the pH value. While, poly(A-Pro-OMe) exhibits a characteristic LCST (Lower Critical Solution Temperature) in aqueous solution. This polymerization procedure could be extended to the synthesis of well-defined block copolymers having the segment derived from amino acids. The tailored amino acid-based materials with unique intelligent properties can be used for various applications, such as controlled release, biochemical sensing, biocompatible materials, and optical resolution.