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. This project describes 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 <50 to >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 non-exposure gaps was developed. In addition, micropatterns with gradient wrinkles were created on the surface (Figure 1). This is the first set of reports that patterns microscale surface wrinkles on elastomer surfaces using infrared laser irradiation. The simple and versatile approach is expected to provide a fast yet controllable way to create wrinkled micropatterns at low cost to facilitate a broad array of studies in surface engineering, cellular biomechanics, and optics. The three published papers go on to describe the proof of concept, the underlying mechanics of the process, and the limitations of the process.

​

The first of three published papers involved in this research project was published by ACS Applied Materials & Interfaces. The second published paper was highlighted as a back cover feature for the scientific journal Lab on a Chip. Additionally, my colleagues and I were selected to present these findings at one of the highest ranked micro-electro-mechanical system conferences in the field, 2018 Solid State Sensors, Actuators, and Microsystems Workshop, alongside those from MIT and University of California, Berkeley. The third paper was published in Lab on a Chip. 

​

** All three papers linked under "Publications" and are available to read upon request **