Ultrafast RAFT polymerization: multiblock copolymers within minutes

The synthesis of multiblock copolymers is often considered to be synthetically challenging and time consuming. In this contribution, the development of a remarkably efficient and versatile procedure to access multiblock copolymers via reversible addition-fragmentation chain transfer (RAFT) polymerization is reported. The robustness and versatility of the RAFT process are demonstrated in this report by preparing multiblock copolymers using uncommon experimental conditions. The synthesis of each block was performed in the presence of air and only required 3 minutes to reach near full monomer conversion. This approach removes the necessity to deoxygenate the solution and allows access to complex copolymer structures in very short time periods. For example, this process allowed the preparation of a heptablock homopolymer with a well-defined architecture in just 21 minutes. We also discuss the limitations inherent to this approach. This strategy is shown to be particularly efficient when blocks with low degrees of polymerization (DP <20) are targeted. For blocks with higher DPs (DP > 50), the procedure is typically limited to the preparation of di- or triblock copolymers.