Shape and feature size control of colloidal crystal-based patterns using stretched polydimethylsiloxane replica molds.

In this work, we fabricated various patterns using colloidal crystals as master molds via the soft lithography method. Even though colloidal crystals consist of spherical colloidal particles, nonspherical shaped patterns such as rectangular or elongated hexagonal shaped patterns can be fabricated using a stretched polydimethylsiloxane (PDMS) replica mold. The pattern shape and feature size can be easily controlled by changing the stretching axis and ratio of the PDMS replica mold. The deformations of the PDMS mold were simulated using the finite element method, and they are consistent with experimental results. The elongated patterns were used as templates to offer new types of colloidal crystal superlattice structures. A proposed pattern-control method will significantly expand the usefulness and diversity of micro/nanopatterning technology.