Photothermal patterning of polydimethylsiloxane†

The surface patterning of polymers is an important approach to enhancing material properties for a large variety of applications. Due to the formation of irreversible crosslinks however, thermoset polymers tend to be challenging to pattern. In this paper we present a novel method of patterning a commonly used thermoset polymer, polydimethylsiloxane (PDMS), through controlled photothermal curing. We show that by incorporating 0.05% carbon black by weight into PDMS and moving a continuous wave-based laser engraver over the surface in a snake pattern, we can photothermally generate micron-scale surface features, and that these patterns can be controlled through laser parameters. Finally, we show that the photothermally patterned PDMS surfaces undergo changes in the optical properties as a result of patterning.