Wettability control on microstructured polypropylene surfaces by means of O2 plasma

Durable and wear resistant polypropylene surfaces with static contact angle (SCA) above 140° have been fabricated using standard photolithographic process and O2 plasma etching followed by thermal annealing at 100 °C. This microfabrication process leads to a hierarchical topography derived from the patterned microstructures and the sub-micron roughness caused by plasma. Hydrophobicity (SCA up to 145°) remained over 14 months after fabrication. This wetting behavior is attributed to the combination of the periodic array of micro-sized pillars with low aspect-ratio and the submicron roughness caused by O2 plasma