Combinatorial generation and replication-directed assembly of complex and varied geometries with thin films of diblock copolymers.
Directed assembly of fine-scale, very complex patterns with a variety of features, including terminations, jogs, disclinations, acute and obtuse bends, and sharp radii of curvature, was achieved with a symmetric poly(styrene-block-methylmethacrylate) (PS-b-PMMA) copolymer. The complex pattern was generated spontaneously by spin coating and annealing a thin film of a lamellae-forming block copolymer on a chemically neutral surface. The resulting "fingerprint" pattern had a domain spacing of 47.5 nm. Oxygen plasma treatment of the block copolymer converted it into an insoluble chemical nanopattern that was quantified by XPS, goniometry, and the wetting behavior of the block copolymer. Spin coating a second thin film of the block copolymer and annealing resulted in directed assembly that replicated the fingerprint pattern, including the most complicated defect structures. A computer vision algorithm was developed and implemented to compare the patterns quantitatively, taking into account inherent differences in image contrast, scale, rotation, and translation.
Park
Sang-Min
SM
Department of Chemical and Biological Engineering, University of Wisconsin--Madison, Madison, Wisconsin 53706, USA.
Ravindran
Prabu
P
La
Young-Hye
YH
Craig
Gordon S W
GS
Ferrier
Nicola J
NJ
Nealey
Paul F
PF