Three-Dimensional Soft Material Micropatterning via Grayscale Photolithography for Improved Hydrophobicity of Polydimethylsiloxane (PDMS)

In this present work, we aim to improve the hydrophobicity of a polydimethylsiloxane (PDMS) surface. Various heights of 3D PDMS micropillars were fabricated via grayscale photolithography, and improved wettability was investigated. Two approaches of PDMS replication were demonstrated, both using a single master mold to obtain the micropillar arrays. The different heights of fabricated PDMS micropillars were characterized by scanning electron microscopy (SEM) and a surface profiler. The surface hydrophobicity was characterized by measuring the water contact angles. The fabrication of PDMS micropillar arrays was shown to be effective in modifying the contact angles of pure water droplets with the highest 157.3-degree water contact angle achieved by implementing a single mask grayscale lithography technique.

Automated summary

In this work, the hydrophobicity of a polydimethylsiloxane (PDMS) surface was improved by fabricating 3D PDMS micropillars of various heights and investigating the wettability improvement. Two methods of PDMS replication were demonstrated using a single master mold to obtain the micropillar arrays. The different heights of the fabricated PDMS micropillars were characterized using scanning electron microscopy (SEM) and a surface profiler. The surface hydrophobicity was evaluated by measuring the water contact angles. The study showed that the fabrication of PDMS micropillar arrays effectively modified the contact angles of water droplets, with the highest water contact angle of 157.3 degrees achieved using a single mask grayscale lithography technique.