Figure 3.

Contact Angle Measurement. (A) Microscopic images of the water droplet interaction with the MSAs. Dome, Petal, and Bell showed the Wenzel state (completely wetted surface), while Bullet and Pillar exhibited the Cassie–Baxter state (non-wetted surface), as seen in the lotus effect. Wenzel state of Dome, Petal, and Bell MSAs were shown in the inset images. (B) Contact angle values as a function to microstructure height. Bullet and Pillar show superhydrophobic properties (contact angle above ~150°), whereas other samples show higher hydrophobic properties than the control. The contact angle values are linearly proportional to the height (R² = 0.98), with all samples but Pillar. R² = 0.92 if including Pillar. Scale bar: (A) 1 mm; Bullet and Pillar: 0.5 mm. Error bars: (B) STDEV. Statistical analysis: One-way ANOVA to see the total effect of height on the hydrophobicity (*** p < 0.001).