Diblock Copolymers: Jaeger, Witten and Grier have started a project to exploit the domain-forming property of diblock copolymer chains for nanofabrication. A diblock copolymer consists of two random-coil homopolymer chains joined end to end. If these two homopolymers are strongly immiscible, the diblock chains microphase self-assemble into a periodic domain structure. The domain spacing depends on the coiled chain lengths (typically 20 - 40 nm) and can be controlled by e.g. the molecular weight of the chains. A wide variety of domain structures may be formed by varying the proportions of the two homopolymer blocks. Recently, this group of collaborators has successfully demonstratedA135 that mesoscopic self-assembly of nanometer-size metal islands can be achieved on diblock-copolymers, producing an island pattern that closely replicates the underlying copolymer domain structure. These results were obtained for gold on PS-PMMA or PS-PVP diblocks, where the gold islands arranged themselves into alternating, stripe-like or hexagonally-ordered domains, respectively. This figure is a color-enhanced transmission electron micrograph [TEM] of self-assembled gold islands with average diameter 6 nm on PS-PMMA stripe domains. TEM work for this project was done across campus in the Life Sciences Center, a cooperative venture arranged by the Materials Center.
Description from the Materials Center Proposal from 1992.
Further Information: Terry L. Morkved, Pierre Wiltzius, H.M. Jaeger, D.G. Grier, and T.A. Witten, "Mesoscopic Self-Assembly of Gold Islands on Diblock-Copolymer Films", Appl. Phys. Lett. 64, 422 (1994)