University of Chicago MRSEC H Jaeger DMR-0213745 (IRG 2) Behavior of Self-Assembled Nanoscale Polymer Domains.
University of Chicago MRSECH JaegerDMR-0213745 (IRG 2)Behavior of Self-Assembled Nanoscale Polymer Domains
Researchers in the Chicago Materials Research Center led by Steven Sibener, in collaboration with partners at Argonne National Laboratory, have developed a novel hierarchical scheme to achieve long-range alignment of cylindrical polymeric nanodomains . Top-down and bottomup approaches are combined by lithographically patterning a substrate with channels that direct the self-assembly of diblock copolymer ultrathin films. Alignment of cylinders is not limited to linear geometries. While straight domains have potential electronic and sensor applications, the available functions of templates with arbitrary morphology are far wider. The above figure depicts the ends of two neighboring channels. Rather than having angular corners, the trough termini are characteristically rounded. Impressively, the polymer cylinders follow the curved interface with minimal introduction of defects. The radius of curvature for these boundaries is 460 nm, or roughly 20 times the polymer domain spacing. Similar results have been observed for a variety of radii of curvature, and further studies by Sibener, Mazenko, Witten, and Jaeger are underway to ascertain the behavior of such films in more complex geometries. Potential applications include nanostructured magnetic, electronic, optical, and catalytic devices.
Tapping mode phase AFM image, 2.9 µm × 2.9 µm, showing aligned cylinders conformably following the curvature of the channel ends. These channels are 900 nm wide and the curvature radius of the channel ends is 460 nm.
 Deepak Sundrani, S.B. Darling, and S.J. Sibener, Langmuir 20 5091-5099 (2004).