Square packing and structural arrangement of ABC triblock copolymer spheres in thin films

Chuanbing Tang, Joona Bang, Gila E. Stein, Glenn H. Fredrickson, Craig J. Hawker, Edward J. Kramer, Michael Sprung, Jin Wang

Research output: Contribution to journalArticlepeer-review

73 Citations (Scopus)


Nanoporous thin films were prepared from poly(ethylene oxide)-b-poly(methyl methacrylate)-b-polystyrene (PEO-b-PMMA-b-PS) ABC triblock copolymer by solvent annealing under high relative humidity followed by UV degradation and acid washing. Ordered half-spheres at the surface that template ordering of spheres below the surface in thin films were formed as a result of the interaction between the hydrophilic PEO segments and water vapor during processing. The spherical block copolymer domains exhibit complex packing behavior on the surface and in the interior. A half-sphere "monolayer" and a half-sphere plus whole sphere "bilayer" were formed in thin films with thicknesses of 43 and 71 nm, respectively, and have hexagonal lattice symmetry. For half-sphere plus two whole sphere "trilayers" with a nominal thickness of 117 nm, coexistence of regions of hexagonal and square packing was observed by transmission electron microscopy, scanning force microscopy, scanning electron microscopy, and grazing-incidence small-angle X-ray scattering. Square packing was consistent with a surface-truncated unit cell of a body-centered cubic lattice with the (100) plane parallel to the surface.

Original languageEnglish
Pages (from-to)4328-4339
Number of pages12
Issue number12
Publication statusPublished - 2008 Jun 24

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry


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