Self-Assembly of Four-Layer Woodpile Structure from Zigzag ABC Copolymer/Aluminosilicate Concertinas

Scanning transmission electron tomography was used to determine the three-dimensional structure of a poly(ethylene-alt-propylene-block-ethylene oxide-block-n-hexyl methacrylate) (PEP-b-PEO-b-PHMA) triblock copolymer/aluminosilicate material with domain volume fractions of f PEP = 0.19, f PEO + aluminosilicate = 0.32, and f PHMA = 0.49. The PEO/aluminosilicate domains formed layers of zigzag-shaped strands (concertinas). Strands were arranged in a four-layer woodpile structure (Sozuer, H. S.; Dowling, J. P. J. Mod. Opt. 1994, 41, 231−239), in which strands in successive layers run in alternate directions (∼75°) and the third and fourth layers are offset. Modeling suggests the PEP and PHMA domains on the outside of each PEO/aluminosilicate strand may stabilize this unusual structure. This result suggests that synthetic macromolecules with multidomain architectures, such as ABC triblock copolymers, can direct the assembly of silica and other ceramic materials into complex new morphologies.