The ability to regulate the activation and deactivation steps via an external stimulus has always been a challenge in polymer chemistry. In an ideal photo-mediated system, whereby high monomer conversion and excellent end group fidelity can be maintained, precise control over the polymer composition and microstructure would be a significant breakthrough. Herein, we report, a versatile, simple and inexpensive method that allows for the synthesis of sequence-controlled multiblock copolymers in a one pot polymerization reaction at ambient temperature. In the absence of a conventional photoredox catalyst and dye-sensitisers, low concentrations of CuBr2 in synergy with Me 6-Tren mediate acrylic block copolymerization under UV irradiation (?max ? 360 nm). Four different acrylate monomers were alternated in various combinations within the polymer composition illustrating the potential of the technique. Narrow disperse undecablock copolymers were obtained (D <1.2) with quantitative conversion achieved between the iterative monomer additions. The effect of the chain length was investigated allowing for higher molecular weight multiblock copolymers to be obtained. This approach offers a versatile and inexpensive platform for the preparation of high-order multiblock functional materials with additional applications arising from the precise spatiotemporal on/off control and resolution when desired.
Anastasaki, A., Nikolaou, V., Pappas, G. S., Zhang, Q., Wan, C., Wilson, P. J., Davis, T. P., Whittaker, M. R., & Haddleton, D. M. (2014). Photoinduced sequence-control via one pot living radical polymerization of acrylates. Chemical Science, 5(9), 3536 - 3542. https://doi.org/10.1039/c4sc01374c