Surface Chemistry of Diblock-Copolymer-Based Nanoporous Materials Takashi Ito, Department of Chemistry, Kansas State University

Cylinder-forming block copolymers (e.g., PS-b-PMMA) provide a means for preparing membranes containing cylindrical nanoscale pores with uniform diameters. The resulting nanoporous membranes can be used to design novel membranes for efficient chemical catalysis and separations. For these future applications, i

n-depth understanding of the chemical properties of the nanopore surface is essential. In the last 12 months, we have demonstrated (1) roughness-induced vertical orientation of cylindrical PMMA domains in a thin PS-b-PMMA film, (2) size-exclusion of PEG-modified PS-b-PMMA-derived nanoporous films for biomolecules, and (3) difference in chemical properties between PS and etched PMMA domains.

A. PEG layer is required for penetration of ferritin through the nanopores.

B. Ferritin (12 nm in diameter) can pass through 20-nm pores, but not 15-nm pores.

C. Selective deposition of ferritin on PS ridges rather than etched PMMA trenches.