Writing Wrinkles on Poly(dimethylsiloxane) (PDMS) by Surface Oxidation with a CO2 Laser Engraver

Surface wrinkles formed by the buckling of a strained stiff layer attached to a soft elastomer foundation have been widely used in a variety of applications. Micropatterning of wrinkled topographies is, however, limited by process/system complexities. In this article, we report an approach to write surface wrinkles with desired pattern geometries on poly(dimethylsiloxane) (PDMS) elastomers using a commercial infrared laser engraver with a spot size of 127 μm. Wrinkled micropatterns with wavelength from 300 μm were obtained in minutes without using special facilities or atmospheres. The minimal achievable pattern sizes of one-dimensional and two-dimensional patterns and the change of the minimal achievable pattern size with wrinkle orientation were investigated under a given set of operating parameters. Sub-spot size patterning was also demonstrated. To reduce surface cracking, a typical problem in large-area wrinkle patterning, a patterning scheme that separates neighboring laser exposure areas by...