Optical Imaging of Large Gyroid Grains in Block Copolymer Templates by Confined Crystallization

摘要: Block copolymer (BCP) self-assembly is a promising route to manufacture functional nanomaterials for applications from nanolithography optical metamaterials. Self-assembled cubic morphologies cannot, however, be conveniently optically characterized in the lab due their structural isotropy. Here, aligned crystallization behavior of semicrystalline-amorphous polyisoprene-b-polystyrene-b-poly(ethylene oxide) (ISO) triblock terpolymer was utilized visualize grain structure microphase-separated morphology. Upon quenching solvent swollen state, ISO first self-assembles into an alternating gyroid morphology, confinement which PEO crystallizes preferentially along least tortuous pathways single morphology with sizes hundreds micrometers. Strikingly, resulting anisotropic alignment crystallites gives rise unique birefringence domains, allows imaging self-assembled ...