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Polymerization‐induced self‐assembly of amino‐acid‐based nano‐objects by reversible addition–fragmentation chain‐transfer dispersion polymerization
Author(s) -
Masuko Kazunori,
Kumano Chiharu,
Sugawara Ryo,
Nakabayashi Kazuhiro,
Mori Hideharu
Publication year - 2021
Publication title -
journal of polymer science
Language(s) - English
Resource type - Journals
eISSN - 2642-4169
pISSN - 2642-4150
DOI - 10.1002/pol.20210292
Subject(s) - chain transfer , polymerization , copolymer , polymer chemistry , raft , reversible addition−fragmentation chain transfer polymerization , chemistry , materials science , organic chemistry , radical polymerization , polymer
A series of amino‐acid‐based amphiphilic diblock copolymer nano‐objects having different morphologies were developed by reversible addition–fragmentation chain‐transfer (RAFT) dispersion polymerization of styrene (St) in methanol. This was mediated by six different hydrophilic poly( N ‐acryloyl amino acid) macro‐chain transfer agents (CTAs), including three carboxylic‐acid‐containing ones, poly( N ‐acryloyl‐ l ‐proline) (PAProOH), poly( N ‐acryloyl‐4‐ trans ‐hydroxy‐ l ‐proline) (PAHypOH), and poly( N ‐acryloyl‐ l ‐threonine) (PAThrOH) prepared by RAFT polymerization, and their methyl ester forms, PAProOMe, PAHypOMe, and PAThrOMe. The effects of polymerization conditions on RAFT dispersion polymerization of St using a dithiocarbamate‐terminated PAProOH was investigated. A systematic study of the effects of monomer conversion and concentration afforded the formation of various morphologies (i.e., spheres, worms, and vesicles). The effects of hydrogen‐bonding and ionic interactions of the macro‐CTAs on the assembled structures of the nano‐objects were evaluated using six different macro‐CTAs. Transforming the products from methanol to water via dialysis produced amino‐acid‐based block copolymer nano‐objects, exhibiting pH‐responsive morphological change, in aqueous solution.