A multiblock copolymer consisting of hard (poly(arylene ether sulfone)) and soft (poly(alkyl disulfide)) segments was successfully synthesized by oxidative coupling of the corresponding thiol-terminated oligomers. Its structure was confirmed by H-1 and C-13 NMR spectroscopy. The GPC data (M-w=82,000, M-w/M-n=2.7) and inherent viscosity (0.67 dL g(-1)) indicated the formation of a high-molecular-weight multiblock copolymer, while AFM and DSC indicated a microphase-separated morphology. Tensile testing of the multiblock copolymer films showed a large elongation at break, which is characteristic of microphase-separated hard/soft multiblock copolymers. Over 90% of the elongation at break of damaged samples (notched or cut) was recovered by UV irradiation. The elongation recovery was proportional to the UV irradiation energy, and the high recovery was achieved by relatively weak irradiation (<170 J cm(-2)). The high content of disulfide bonds in the multiblock copolymer resulted in a lower self-healing energy. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1358-1365