Sequence-Controlled Primary Amine-based Copolymers Via Light On-off Switchable Room Temperature RAFT Polymerization

This paper first report a novel direct method for the syntheses of N-(2-aminoethyl)acrylamide hydrochloride (AEAM) without any time-consuming protecting group chemistry.The aqueous reversible addition-fragmentation chain transfer (RAFT) polymerization ofAEAM monomer under mild visible light irradiation at20oC revealed to be highly rapid andwell-controlled. Moreover,2-(4-Imidazolyl)ethyl Acrylamide (IEAM) Monomer weresynthesized and the aqueous RAFT polymerization of IEAM monomer were performed with ahighly rapid and well-controlled manner. Furthermore, The RAFT copolymerization ofAEAM and IEAM were studied under such conditions. The extense K-T method were used todetermine the reactivity ratios of AEAM and IEAM. Inspired from the temporal control of thephotopolymerization, control over the sequence distribution of primary amine-basedmonomer AEAM is possible when the visible light source is alternately switched on and off inbetween sequential addition of different monomers. The polymerization of IEAM werepaused by simply turning the light “off” at a desired monomer conversion, then quantitativeAEAM monomer were added, with subsequent restart the polymerization by turning the light“on”. The polymerization going on until exhausts the monomers. Well-definedPIEAM-b-PAEAM block copolymer, PIEAM-b-P(AEAM-r-IEAM) andPIEAM-b-P(AEAM-r-IEAM)-PNIPAM copolymer with designed sequence distribution weresynthesized in such a way that based on the highly rapid visible-light-inducedroom-temperature aqueous RAFT polymerization.