posted on 2014-05-27, 00:00authored byGuillaume Gody, Thomas Maschmeyer, Per B. Zetterlund, Sébastien Perrier
We describe an optimized method to
prepare multiblock copolymers.
The approach is based on our previously reported use of reversible
addition–fragmentation chain transfer (RAFT) polymerization,
which here has been optimized into a fast, versatile, efficient, and
scalable process. The one-pot, multistep sequential polymerization
proceeds in water, to quantitative yields (>99%) for each monomer
addition, thus circumventing requirements for intermediate purification,
in 2 h of polymerization per block. The optimization of the process
is initially demonstrated via the synthesis of a model decablock homopolymer
(10 blocks) of 4-acryloylmorpholine with an average degree of polymerization
of 10 for each block (Đ =
1.15 and livingness >93% for the final polymer). Both the potential
and the limitations of this approach are illustrated by the synthesis
of more complex high-order multiblock copolymers: a dodecablock copolymer
(12 blocks with 4 different acrylamide monomers) with an average degree
of polymerization of 10 for each block and two higher molecular weight
pentablock copolymers (5 blocks with 3 different acrylamide monomers)
with an average degree of polymerization of 100 per block.