Spontaneous formation of interdigitated array pattern in wrinkled gold films deposited on poly(dimethylsiloxane) elastomer

Abstract

In this study, we attempted to produce a gold coating on a glass slide with an interdigitated array (IDA) pattern through a series of processes including spontaneous pattern formation as a key step instead of using photolithographic micromachining processes. In the first step, a gold film was formed by sputter deposition onto a strip of poly(dimethylsiloxane) (PDMS) elastomer. As part of the deposition process, the strip was heated because of the excess kinetic energy of the sputtered atoms. As the strip cooled to room temperature after the deposition, it thermally shrunk, causing the gold film to wrinkle because of buckling instability. Most of the wrinkles were oriented in a direction perpendicular to the lengthwise direction of the strip. In the second step, a glass strip that was narrower than the PDMS strip was placed on the PDMS strip. Sputter deposition of gold was repeated, resulting in the formation of wrinkles with an IDA pattern. Finally, this pattern was replicated on an elastomeric stamp surface that was then used for patterning a gold coating on a glass slide using microcontact printing techniques. We patterned a gold coating on a glass slide to be an interdigitated array (IDA) pattern using spontaneous pattern formation as a key step. First, gold was sputter deposited onto a strip of poly(dimethylsiloxane) (PDMS). Because the strip was heated during the deposition, the gold film wrinkled. Next, a glass strip was placed on the PDMS strip and gold was deposited again. Wrinkles with an IDA pattern were spontaneously formed. The obtained wrinkles were used to pattern a gold coating.