Emergence of layered nanoscale mesh networks through intrinsic molecular confinement self-assembly

Block copolymer self-assembly is a powerful tool for 2D nanofabrication; however, its extension to complex 3D network structures, which would be useful for a range of applications, is limited. Here, we report a simple method to generate unprecedented 3D mesh morphologies through intrinsic molecular confinement self-assembly. We designed triblock bottlebrush polymers with two Janus domains: one perpendicular and one parallel to the polymer backbone. The former enforces a lamellar superstructure that intrinsically confines the intra-layer self-assembly of the latter, giving rise to a mesh-like monoclinic M15 network substructure with excellent long-range order. Dissipative particle dynamics simulations show that the spatial constraints exerted on the polymer backbone drive the emergence of M15, as well as a tetragonal T131 in the strong segregation regime. This work demonstrates intrinsic molecular confinement as a path to bottom-up assembly of new geometrical phases of soft matter, extending the capabilities of block copolymer nanofabrication.