Novel soft stamp development for direct micro- and nano-patterning of macroscopic curved surfaces

Abstract

Surface topographical patterning is a simple way to functionalize surfaces without changing material chemistry. Topographical patterning of nonplanar surfaces has remained a challenge, despite sought after applications in microfluidics, optics, and biomedical technologies. Here the authors develop transparent, reusable soft molds that allow facile micro- and nanopatterning of macroscopically curved surfaces. The authors use bilayer molds with a soft backing and a hard pattern carrying layer to overcome challenges that arise from the opposing need for mold compliance (to allow conformal contact with nonflat substrates) and rigidity (to maintain patterned feature resolution and fidelity). With our approach, high yield curved surface patterning (>98%) over large (2 × 1 cm) area can be effectively achieved. Structure replication down to 80 nm resolution is demonstrated.