Block Architectures in 2D Polymer Networks Fabricated via Sequential Copolymerization in a Metal-Organic Framework.

Two-dimensional (2D) polymer network monolayers with novel block architectures were fabricated via sequential copolymerization within a pillared-layer metal-organic framework (MOF) that served as the reaction template. The MOF provides a confined 2D nanospace, restricting the crosslinking copolymerization of vinyl monomers to two dimensions. Sequential crosslinking copolymerization of methyl methacrylate and styrene, regulated by the reversible addition-fragmentation chain transfer (RAFT) process, resulted in the formation of 2D block architectures with 'patchy' domains consisting of crosslinked poly(methyl methacrylate) and polystyrene segments. Atomic force microscopy revealed that the resulting block monolayers exhibited varied morphologies on substrates, attributed to their intrinsic flexibility in 2D conformation, which facilitated microphase separation of the 2D segments within monolayers, leading to the unique aggregation morphologies. The unprecedented block topology in 2D polymeric monolayers presented in this study introduces a novel strategy for designing 2D polymeric nanomaterials with flexible yet anisotropic properties.