Figure 10.

Coexistence of two superhydrophobic modes. With feeble hydrophobicity (cosθ_c < cosθ < 0), the apparent contact angle is theoretically given by the relation of Wenzel while for strong hydrophobicity (cosθ < cosθ_c), the apparent contact angle follows the relation of Cassie–Baxter. However, in practice, an average hydrophobicity generally involves a metastable configuration of Cassie–Baxter (dotted lines)