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.

Formation of aligned needle‐like crystals of 9,10‐dibromoanthracene in small droplets

“…All wrinkles were perpendicular to the long axis of the PDMS strip (Figure 4c). Although the swelling‐induced stress in the oxidized layer was intrinsically isotropic, it was reduced near the edge of the strip where expansion of the layer in the direction perpendicular to the axis was relatively uninhibited 40 . Because the residual stress was present only in the direction parallel to the axis, the formation of regular wrinkles occurred as shown in Figure 4c.…”

Stretchable Conductors Fabricated by Stencil Lithography and Centrifugal Force-Assisted Patterning of Liquid Metal

“…The result shows a resistivity of 0.31 Ω·μm for the sputter deposited Au by using a stencil mask (Figure S5, SI). The measured resistiviy of a sputtered Au thin film is more than ten times of the value of bulk Au, which is attributed to random cracks and surface wrinkles in the Au film formed during the sputtering process. , To calculate the resistivity of patterned EGaIn, the resistance is plotted as a function of the inverse of the EGaIn cross-section area for different lengths (Figure a). The cross-section area of each device is calculated by integrating the profile measured by confocal microscopy (S neox, Sensofar) and subtracted from the area of the underneath adhesive layer.…”